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    Effects of yeast and yeast cell wall polysaccharides supplementation on beef cattle growth performance, rumen microbial populations and lipopolysaccharides production
    PENG Quan-hui, CHENG Long, KANG Kun, Tian Gang, Mohammad AL-MAMUN, XUE Bai, WANG Li-zhi, ZOU Hua-wei, Mathew Gitau GICHEHA, WANG Zhi-sheng
    2020, 19 (3): 810-819.   DOI: 10.1016/S2095-3119(19)62708-5
    Abstract109)      PDF in ScienceDirect      

    This experiment was conducted to investigate the effects of live yeast and yeast cell wall polysaccharides on growth performance, rumen function and plasma lipopolysaccharides (LPS) content and immunity parameters of beef cattle.  Forty Qinchuan cattle were randomly assigned to one of four treatments with 10 replicates in each treatment.  The dietary treatments were: control diet (CTR), CTR supplemented with 1 g live yeast (2×1010 live cell g–1 per cattle per day (YST1), CTR supplemented with 2 g live yeast per cattle per day (YST2) and CTR supplemented with 20 g of yeast cell wall polysaccharides (30.0%≤β-glucan≤35.0%, and 28.0%≤mannanoligosaccharide≤32.0%) per cattle per day (YCW).  The average daily gain was higher (P=0.023) and feed conversion ratio was lower (P=0.042) for the YST2 than the CTR.  The digestibility of neutral detergent fiber (P=0.039) and acid detergent fiber (P=0.016) were higher in yeast supplemented groups.  The acetic acid:propionic acid of the YST2 was lower compared with the CTR (P=0.033).  Plasma LPS (P=0.032), acute phase protein haptoglobin (P=0.033), plasma amyloid A (P=0.015) and histamine (P=0.038) were lower in the YST2 compared with the CTR.  The copies of fibrolytic microbial populations such as Fibrobacter succinogenes S85, Ruminococcus albus 7 and Ruminococcus flavefaciens FD-1 of the YST2 were higher (P<0.001), while the copies of typical lactate producing bacteria Streptococcus bovis JB1 was lower (P<0.001) compared with the CTR.  Little differences were observed between the CTR, YST1 and YCW in growth performance, ruminal fermentation characteristics, microbial populations, immunity indices and total tract nutrient digestibility.  It is concluded that the YST2 could promote fibrolytic microbial populations, decrease starch-utilizing bacteria, reduce LPS production in the rumen and LPS absorption into plasma and decrease inflammatory parameters, which can lead to an improvement in growth performance in beef cattle. 

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    The effect of lactic acid bacteria inoculums on in vitro rumen fermentation, methane production, ruminal cellulolytic bacteria populations and cellulase activities of corn stover silage
    GUO Gang, SHEN Chen, LIU Qiang, ZHANG Shuan-lin, SHAO Tao, WANG Cong, WANG Yong-xin, XU Qing-fang, HUO Wen-jie
    2020, 19 (3): 838-847.   DOI: 10.1016/S2095-3119(19)62707-3
    Abstract94)      PDF in ScienceDirect      
    The objective of this study was to investigate the effect of lactic acid bacteria (LAB) inoculums on fermentation quality and in vitro digestibility of corn stover silage. Corn stover was ensiled without (control) or with Lactobacillus plantarum (LP), Enterococcus faecalis (EF), and Enterococcus mundtii (EM) for 45 days. The fermentation characteristics were assessed, and subsequent in vitro dry matter digestibility (DM-D), neutral detergent fiber digestibility (NDF-D), volatile fatty acids (VFA), methane (CH4 ) production, cellulolytic bacteria proportions and their activities per corn stover silage were also determined. There was no significant difference (P>0.05) among the silage pH, lactic acid, crude protein (CP), water soluble carbohydrates (WSC) and lignocelluloses contents of different treatments. The relative proportions of Ruminococcus flavefaciens and Fibrobacter succinogenes, carboxymethyl-ocellulose and β-glycosidase activities, DM-D, NDF-D, and VFA production of in vitro incubation was higher (P<0.05) for silages inoculated with LP and EF than those of the control silage. Silage inoculated with LP showed the lowest (P<0.05) CH4 production per unit yield of VFA, which was positively corresponded to the lowest (P<0.05) ratio of acetate to propionate. In summary, the ensiling fermentation quality and subsequent utilization of corn stover silage were efficiently improved by inoculated with L. plantarum.
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    Effects of palm fat powder and coated folic acid on growth performance, ruminal fermentation, nutrient digestibility and hepatic fat accumulation of Holstein dairy bulls
    ZHANG Zhen, LIU Qiang, WANG Cong, GUO Gang, HUO Wen-jie, ZHANG Yan-li, PEI Cai-xia, ZHANG Shuan-lin
    2020, 19 (4): 1074-1084.   DOI: 10.1016/S2095-3119(19)62752-8
    Abstract91)      PDF in ScienceDirect      
    This study evaluated the effects of palm fat powder (PFP) and coated folic acid (CFA) on growth performance, ruminal fermentation, nutrient digestibility, microbial enzyme activity, microflora, hepatic lipid content and gene expression in dairy bulls.  Forty-eight Chinese Holstein bulls ((362±12.4) days of age and (483±27.1) kg of body weight (BW)) were assigned to four groups in a completely randomized design with a 2×2 factorial arrangements.  Supplemental PFP (0 or 30 g PFP kg–1 dietary dry matter (DM)) and CFA (0 or 120 mg FA d–1 as CFA) were mixed into the top one-third of a total mixed ration.  The study included a 20-day adaptation period and followed by a 90-day collection period.  The lower (P<0.01) feed conversion ratio with PFP or CFA addition resulted from the constant DM intake and the higher (P<0.05) average daily gain.  The higher (P<0.05) ruminal pH, ether extract digestibility, microbial α-amylase activity, Butyrivibrio fibrisolvens copy, and expression of peroxisome-proliferator-activated receptor α (PPARα) and carnitine palmitoyl transferase-1 (CPT1), and lower ruminal total volatile fatty acids (VFA) concentration, acetate to propionate ratio, neutral detergent fibre (NDF) digestibility, copies of total protozoa and Ruminococcus flavefaciens, and expression of sterol regulatory element binding protein-1 (SREBP1) and acetyl-coenzyme A carboxylase α (ACACA) were observed for PFP addition.  Supplementation with CFA increased (P<0.05) ruminal total VFA concentration, acetate to propionate ratio, digestibility of DM, organic matter, crude protein and NDF, activity of cellobiase, pectinase and α-amylase, copies of selected microbial except for total protozoa, as well as expression of PPARα, but decreased (P<0.05) ruminal pH, and expression of SREBP1 and ACACA.  The PFP×CFA interaction (P<0.05) was observed for ammonia N, hepatic TG content, and mRNA expression of CPT1 and FAS.  There had no significant difference in hepatic TG content when CFA was supplemented in the diet without PFP addition, the lower (P=0.001) hepatic TG content was observed when CFA was supplemented in the diet with PFP addition.  The higher (P<0.05) mRNA expression of CPT1, and the lower (P<0.05) mRNA expression of FAS and ammonia N concentration were observed when CFA was supplemented in diet either without or with PFP addition.  The results indicated that supplementation of CFA in PFP diet was more effective on increasing hepatic CPT1 expression, and decreasing ammonia N, hepatic TG content and FAS expression than in diet without PFP.  Supplementation with PFP or CFA improved growth performance of dairy bulls by promoting nutrient utilization, microbial enzyme activity, microflora, and hepatic gene expression.
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    Effect of transferring lignocellulose-degrading bacteria from termite to rumen fluid of sheep on in vitro gas production, fermentation parameters, microbial populations and enzyme activity
    Ayoub AZIZI, Afrooz SHARIFI, Hasan FAZAELI, Arash AZARFAR, Arjan JONKER, Ali KIANI
    2020, 19 (5): 1323-1331.   DOI: 10.1016/S2095-3119(19)62854-6
    Abstract72)      PDF in ScienceDirect      
    The digestive tract of termite (Microcerotermes diversus) contains a variety of lignocellulose-degrading bacteria with exocellulases enzyme activity, not found in the rumen, which could potentially improve fiber degradation in the rumen.  The objectives of the current study were to determine the effect of inoculation of rumen fluid (RF) with three species of bacteria isolated from termite digestive tract, Bacillus licheniformis, Ochrobactrum intermedium, and Microbacterium paludicola, on in vitro gas production (IVGP), fermentation parameters, nutrient disappearance, microbial populations, and hydrolytic enzyme activities with fibrous wheat straw (WS) and date leaf (DL) as incubation substrate.  Inoculation of RF with either of three termite bacteria increased (P<0.05) ammonia-N concentration compared with the control group (free of termite gut bacteria).  Termite bacteria inoculation had no effect (P>0.05) on gas production characteristics, dry matter, organic matter and neutral detergent fiber disappearance, pH, and concentration and composition of volatile fatty acids.  Population of proteolytic bacteria and protozoa, but not cellulolytic bacteria, were increased (P<0.05) when RF was inoculated with termite bacteria with both WS and DL substrates.  Inoculation of RF with termite bacteria increased protease activity, while activities of carboxymethyl-cellulase, microcrystalline-cellulase, α-amylase and filter paper degrading activity remained unchanged (P>0.05).  Overall, the results of this study indicated that transferring lignocellulose-degrading bacteria, isolated from digestive tract of termite, to rumen liquid increased protozoa and proteolytic bacteria population and consequently increased protease activity and ammonia-N concentration in vitro, however, no effect on fermentation and fiber degradation parameters were detected.  These results suggest that the termite bacteria might be rapidly lysed by the rumen microbes before beneficial effects on the rumen fermentation process could occur.
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    Effects of different molecular weights of chitosan on methane production and bacterial community structure in vitro
    TONG Jin-jin, ZHANG Hua, WANG Jia, LIU Yun, MAO Sheng-yong, XIONG Ben-hai, JIANG Lin-shu
    2020, 19 (6): 1644-1655.   DOI: 10.1016/S2095-3119(20)63174-4
    Abstract66)      PDF in ScienceDirect      
    As a new feed additive, chitosan has been shown in recent years to have a certain role in reducing methane emissions from the gastrointestinal tracts of ruminants.  However, the effects of chitosan with different molecular weights on rumen fermentation, methane production and bacterial community structure are not yet clear.  A basal diet without chitosan served as the control (CTL), and the treatment diets were supplemented with chitosan with different molecular weights: 1 000 (1K), 3 000 (3K), 5 000 (5K), 50 000 (5W) and 200 000 (20W) dry matter (DM).  Six fermentation units per treatment were established.  Gas chromatography was used to measure the concentrations of methane, H2 and volatile fatty acids (VFAs).  The bacterial 16S rRNA genes were sequenced with an Illumina MiSeq platform and analysed to reveal the relative abundances of bacterial community taxa.  The results showed that the propionate proportion was significantly increased by the addition of chitosan with different molecular weights (P<0.05), while methane production and the acetate proportion were significantly decreased (P<0.05).  The relative abundances of Rikenellaceae_RC9_gut_group and Prevotellaceae_UCG_003 were significantly increased in the 3K chitosan group compared with the CTL group, whereas the relative abundance of Ruminococcaceae_NK4A214_group was significantly decreased (P<0.05).  Correlation analyses of the relative abundances of the bacterial genera showed that Prevotella was positively related to propionate production (P<0.05).  In conclusion, 3K chitosan could reduce methane production by replacing fibrolytic bacteria (Firmicutes and Fibrobacteres) with amylolytic bacteria (Bacteroidetes and Proteobacteria) in the bacterial community structure.
     
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    Effect of dietary supplementation of pyrroloquinoline quinone disodium on growth performance, meat quality and antioxidative ability of broilers
    LIU Guo-qing, SUN Guang-ming, LIAO Xiu-dong, HUANG Jian-zhong, GUO Mei-jin, ZHANG Li-yang, GUO Yan-li, LU Lin, LUO Xu-gang
    2020, 19 (7): 1850-1856.   DOI: 10.1016/S2095-3119(19)62851-0
    Abstract108)      PDF in ScienceDirect      
    This study was conducted to investigate the effect of dietary supplementation with pyrroloquinoline quinone (PQQ) in the form of PQQ disodium (PQQ·Na2) on the growth performance, carcass traits, meat quality and antioxidative ability of broilers.  A total of 720 one-d-old Arbor Acres male broilers were randomly allocated to 1 of 6 treatments with 8 replicates of 15 birds per replicate in a completely randomized design.  Birds were fed a PQQ·Na2-unsupplemented corn-soybean meal basal diet (control) or the basal diet supplemented with 0.1, 0.2, 0.3, 0.4 or 0.5 mg PQQ·Na2 kg–1 for 42 d.  Compared with the control chicks, the chicks fed the diets supplemented with PQQ·Na2 had lower (P<0.05) feed:gain (F/G) during the grower phase and drip losses of breast muscles on day 42.  As supplemental PQQ·Na2 level increased, plasma total antioxidant capacity (T-AOC) on d 42, liver T-AOC on d 21 and heart T-AOC on d 21 and 42 increased linearly (P<0.05), but malondialdehyde concentrations in plasma, liver and heart on d 21 or 42 decreased linearly (P<0.001) or quadratically (P<0.005).  The results from the present study indicate that dietary supplemental PQQ·Na2 can improve antioxidant ability and meat quality  of broilers, and in general, it is implied that the optimal supplemental PQQ·Na2 level is 0.1 mg kg–1 of diet for broilers from 1 to 42 d of age.
     
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    Kinetics of selenium absorption in ligated small intestinal loops of chicks
    LIU Guo-qing, ZHANG Shu-min, AN Zhi-min, FENG Yan-zhong, DONG Xue-yu, LI Su-fen, LU Lin, ZHANG Li-yang, WANG Run-lian, LUO Xu-gang, LIAO Xiu-dong
    2020, 19 (8): 2095-2102.   DOI: 10.1016/S2095-3119(20)63194-X
    Abstract102)      PDF in ScienceDirect      
    Selenium (Se) is an essential trace element that has a large number of biological functions for broilers.  However, the absorption kinetics of Se from sodium selenite in the small intestine of broilers remains unclear.  Therefore, two experiments were conducted with 28-d-old commercial male broilers to study the kinetics of Se absorption in ligated small intestinal segments.  In experiment 1, the Se absorption in duodenal, jejunal, and ileal segments at different post-perfusion time points (0, 20, 40, 60, 80, 100 and 120 min) were compared.  In experiment 2, a kinetic study of Se absorption was conducted with the duodenal, jejunal, and ileal loops perfused with solutions containing 0, 0.0375, 0.075, 0.15, 0.30, or 0.60 μg mL–1 of Se as sodium selenite, and Se contents in perfusates were determined at 100 min after perfusion.  The results from experiment 1 showed that the Se absorption increased in an asymptotic response (P<0.0001) to post-perfusion time within 120 min in all the small intestinal segments, but increased linearly (P<0.0001) at less than 100 min after perfusion in duodenal and ileal segments, while more than 96.0% of the maximum Se absorption occurred at 100 min after perfusion in each small intestinal segment.  In experiment 2, there was no difference (P>0.05) in the Se absorption rate among different ligated small intestinal segments perfused with solutions containing 0.0375–0.15 μg mL–1 of Se, however, the Se absorption rate was higher (P<0.05) in the jejunum than that in the duodenum perfused with solutions containing 0.30–0.60 μg mL–1 of Se.  The kinetic curves of Se absorption demonstrated that the Se absorption was a saturated carrier-mediated process in the duodenum, and the maximum absorption rate was 1 271 pg min–1 cm–1; whereas the Se absorptions were a non-saturated diffusion process in the jejunum and ileum, and the diffusive constants were 2 107 and 1 777 cm2 min–1, respectively.  The results from the present study indicate that the jejunum is the main Se absorption site, and the Se absorption is a saturated carrier-mediated process in the duodenum, but a non-saturated diffusion process in the jejunum and ileum of broilers.
     
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    Effect of dietary calcium or phosphorus deficiency on bone development and related calcium or phosphorus metabolic utilization parameters of broilers from 22 to 42 days of age
    YANG Yun-feng, XING Guan-zhong, LI su-fen, SHAO Yu-xin, ZHANG Li-yang, LU Lin, LUO Xu-gang, LIAO Xiu-dong
    2020, 19 (11): 2775-2783.   DOI: 10.1016/S2095-3119(20)63302-0
    Abstract50)      PDF in ScienceDirect      
    This experiment was conducted to investigate the effect of dietary calcium (Ca) or phosphorus (P) deficiency on bone development and related Ca or P metabolic utilization parameters of broilers from 22 to 42 days of age based on our previous study, which indicated that dietary Ca or P deficiency impaired the bone development by regulating related Ca or P metabolic utilization parameters of broilers from 1 to 21 days of age.  A total of 504 one-day-old Arbor Acres male broilers were randomly assigned to 1 of 4 treatments with 7 replicates in a completely randomized design, and fed the normal control and Ca- or P-deficient diets from 1 to 21 days of age.  At 22 days of age, the broilers were further fed the normal control diet (0.90% Ca+0.35% non-phytate P (NPP)), the P-deficient diet (0.90% Ca+0.18% NPP), the Ca-deficient diet (0.30% Ca+0.35% NPP) or the Ca and P-deficient diet (0.30% Ca+0.18% NPP), respectively.  The results showed that dietary Ca or P deficiency decreased (P<0.05) tibia bone mineral density (BMD), bone breaking strength (BBS), ash content, tibia ash Ca content and serum P content on days 28 and 42, but increased (P<0.05) tibia alkaline phosphatase (ALP) activity of broilers on day 42 compared with the control group.  Furthermore, the broilers fed the P-deficient diet had the lowest (P<0.05) tibia BMD, BBS, ash content, serum P content and the highest (P<0.05) serum Ca content on day 28 compared with those fed the Ca-deficient or Ca and P-deficient diets.  The results from the present study indicated that the bone development and related Ca or P metabolic utilization parameters of broilers were the most sensitive to dietary P deficiency, followed by dietary Ca deficiency or Ca and P-deficiency; dietary Ca or P deficiency impaired the bone development possibly by regulating serum Ca and P contents as well as tibia Ca content and ALP activity of broilers from 22 to 42 days of age.
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    Alginate oligosaccharides preparation, biological activities and their application in livestock and poultry 
    LIU Ming, LIU Lei, ZHANG Hong-fu, YI Bao, Nadia EVERAERT
    2021, 20 (1): 24-34.   DOI: 10.1016/S2095-3119(20)63195-1
    Abstract96)      PDF in ScienceDirect      
    Alginate oligosaccharides (AOS), belonging to the class of functional marine oligosaccharides, are low-molecular polymers linked by β-1,4-mannuronic acid (M) and α-1,4-guluronic acid (G), which could be classically obtained by enzymatic hydrolysis of alginate. With low viscosity and good water solubility, as well as anti-oxidant, immune regulation, anti-bacterial and anti-inflammatory activities, AOS have been widely used in medical science and functional food, green agriculture and other fields. As new bio-feed additives, AOS have broad potential applications in animal husbandry. In this review, the sources of alginate, chemical structure and preparation methods of AOS, and their biological activities and application in livestock and poultry are summarized. We expect this review could contribute to lay a foundation of application and further research for AOS in livestock and poultry.
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    Effects of selenium source and level on growth performance, antioxidative ability and meat quality of broilers
    WANG Chuan-long, XING Guan-zhong, WANG Li-sai, LI Su-fen, ZHANG Li-yang, LU Lin, LUO Xu-gang, LIAO Xiu-dong
    2021, 20 (1): 227-235.   DOI: 10.1016/S2095-3119(20)63432-3
    Abstract123)      PDF in ScienceDirect      
    This experiment was conducted to investigate the effects of selenium (Se) source and level on growth performance, carcass traits, antioxidative ability and meat quality of broilers.  A total of 320 one-d-old Arbor Acres commercial broilers were randomly assigned to 1 of 5 treatments with 8 replicates in a completely randomized design involving a 2×2 factorial arrangement of treatments plus one Se-unsupplemented basal diet control for 42 d.  The two Se sources were sodium selenite and Se yeast, and the two supplemental Se levels were 0.20 and 0.40 mg Se kg–1.  The results showed that broilers fed the Se-supplemented diets had higher (P<0.05) average daily gain and average daily feed intake from 22 to 42 d of age, eviscerated yield and abdominal fat percentages, Se concentrations and glutathione peroxidase (GSH-Px) activities in breast and thigh muscles on d 42, and lower (P<0.05) feed/gain from 1 to 21 and 22 to 42 d of age, mortality from 22 to 42 d of age and malondialdehyde (MDA) concentration in thigh muscle on d 42 than those fed the control diet.  Broilers fed the diets supplemented with Se yeast had higher (P<0.05) pH value and lower (P<0.05) shear force in thigh muscle than those fed the diets supplemented with sodium selenite.  Additionally, broilers fed the diets supplemented with 0.40 mg Se kg–1 had lower (P<0.05) shear force in thigh muscle and higher (P<0.05) GSH-Px activities in breast and thigh muscles than those fed the diets supplemented with 0.20 mg Se kg–1.  Furthermore, broilers fed the diet supplemented with Se yeast at 0.40 mg Se kg–1 had higher (P<0.05) Se concentrations in breast and thigh muscles than those fed the diet supplemented with Se yeast at 0.20 mg Se kg–1, but no differences (P<0.05) were observed in these indices of broilers fed the diets supplemented with sodium selenite between 0.20 and 0.40 mg Se kg–1.  The results from the present study indicated that supplemental Se could increase the growth performance, muscle Se concentration and antioxidative ability of broilers; and the Se from Se yeast was more effective than the Se from sodium selenite in improving meat quality of broilers.
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    Effects of rearing system (floor vs. cage) and sex on performance, meat quality and enteric microorganism of yellow feather broilers
    WANG Lai-di, ZHANG Yang, KONG Ling-ling, WANG Zhi-xiu, BAI Hao, JIANG Yong, BI Yu-lin, CHANG Guo-bin, CHEN Guo-hong
    2021, 20 (7): 1907-1920.   DOI: 10.1016/S2095-3119(20)63420-7
    Abstract155)      PDF in ScienceDirect      
    This study investigated the effects of floor and cage rearing systems on performance, meat quality, and enteric microorganisms of male and female yellow feather broilers.  Two hundred Xueshan chickens (42 days old; 100 of each sex) were divided into four groups, according to sex and rearing system (stainless-steel cage or litter floor).  Male and cage-reared broilers exhibited better (P<0.001) performance and higher (P≤0.001) eviscerated percentage than female and floor-reared broilers.  The interaction between rearing system and sex had an effect (P<0.05) on the percentage of breast and thigh muscles.  Female floor-reared broilers presented the highest (P<0.02) percentage of breast and thigh muscles among all the groups.  In both sexes, the abdominal fat content in cage-reared broilers was higher (P<0.01) than that in floor-reared broilers.  Female cage-reared broilers exhibited better (P<0.05) meat quality of breast muscle than other groups.  An analysis of welfare observations indicated that the feather quality of floor-reared broilers was better (P<0.01) than that of cage-reared broilers, whereas the gait scores were not significantly affected (P>0.05) by rearing system.  The enteric microbiota assessment by 16S rRNA amplicon-based sequencing showed that Firmicutes, Proteobacteria, and Bacteroidetes were the most prevalent phyla in both rearing systems, and that the cecum was relatively stable in terms of microbiome composition.  Floor-reared broilers exhibited a richer diversity of bacteria in the intestinal tract than cage-reared broilers, while alpha diversity was not significantly different (P>0.05) among the groups.  The ratio of Bacteroidetes to Firmicutes and the abundance of Helicobacter and Romboutsia could potentially affect the production of broilers.  These findings indicate that cage rearing improved the production of male Xueshan broilers, which may be due to the difference in enteric microbiota between cage and floor rearing systems. 
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    Effects of formic acid and corn flour supplementation of banana pseudostem silages on nutritional quality of silages, growth, digestion, rumen fermentation and cellulolytic bacterial community of Nubian black goats
    Zhang Hao, Cheng Xuan, Mabrouk ELSABAGH, Lin Bo, Wang Hong-rong
    2021, 20 (8): 2214-2226.   DOI: 10.1016/S2095-3119(20)63470-0
    Abstract101)      PDF in ScienceDirect      
    The objective of this study was to evaluate the effects of adding formic acid and corn flour supplementation to banana pseudostem silages on the nutritional quality of these silages, growth, digestion, rumen fermentation and cellulolytic bacterial community of Nubian black goats fed these silages.  Banana pseudostem silage was prepared either conventionally without any additives (CON) or mixed with 0.6% formic acid (F), 10% corn flour (C), or both (F+C).  Four experimental diets containing 40% of the corresponding silages were designed with roughage to concentrate ratio of 50:50 (dry matter (DM) basis).  A total of 48 Nubian black castrated goats (body weight (BW), (22.64±1.82) kg; 4-mon-old) were randomized into one of the four treatment groups with 12 replicates of one castrated goat per replicate for each treatment in a completely randomized design.  Each group was fed on one of the four experimental diets for 40 days.  A factorial arrangement of treatments of 2 (formic acid levels: 0 and 0.6%)×2 (corn flour: 0 and 10%) was adopted.  Formic acid supplementation increased (P<0.05) average daily gain, as well as lactic acid, propionate and butyric acid and water-soluble carbohydrate concentrations, but decreased (P<0.05) the feed conversion rate, pH value, acetate/propionate ratio, and butyric acid concentration relative to the CON group.  Corn flour supplementation increased (P<0.05) the apparent digestibility of crude protein, neutral detergent fiber, and non-fibrous carbohydrate and Fibrobacter succinogenes, Ruminococcus albus, and Butyrivibrio fibrisolvens populations, but decreased (P<0.05) the Ruminococcus flavefaciens population relative to the CON group.  There were no F×C treatment interactions (P>0.05) for any of the other indices except for the apparent digestibility of non-fibrous carbohydrate (NFC) (P<0.05).  The results demonstrated that adding 0.6% formic acid and 10% corn flour supplementation to banana pseudostem silages improved the nutritional quality of these silages and enhanced the growth performance of Nubian black castrated goats by improving apparent nutrient digestibility, and regulating ruminal fermentation and bacteria populations.
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    Quantification and prediction of enteric methane emissions from Chinese lactating Holstein dairy cows fed diets with different dietary neutral detergent fiber/non-fibrous carbohydrate (NDF/NFC) ratios
    DONG Li-feng, JIA Peng, LI Bin-chang, WANG Bei, YANG Chun-lei, LIU Zhi-hao, DIAO Qi-yu
    2022, 21 (3): 797-811.   DOI: 10.1016/S2095-3119(21)63825-X
    Abstract251)      PDF in ScienceDirect      
    Methane (CH4) emissions from ruminant production are a significant source of anthropogenic greenhouse gas production, but few studies have examined the enteric CH4 emissions of lactating dairy cows under different feeding regimes in China.  This study aimed to investigate the influence of different dietary neutral detergent fiber/non-fibrous carbohydrate (NDF/NFC) ratios on production performance, nutrient digestibility, and CH4 emissions for Holstein dairy cows at various stages of lactation. It evaluated the performance of CH4 prediction equations developed using local dietary and milk production variables compared to previously published prediction equations developed in other production regimes.  For this purpose, 36 lactating cows were assigned to one of three treatments with differing dietary NDF/NFC ratios: low (NDF/NFC=1.19), medium (NDF/NFC=1.54), and high (NDF/NFC=1.68).  A modified acid-insoluble ash method was used to determine nutrient digestibility, while the sulfur hexafluoride technique was used to measure enteric CH4 emissions.  The results showed that the dry matter (DM) intake of cows at the early, middle, and late stages of lactation decreased significantly (P<0.01) from 20.9 to 15.4 kg d–1, 15.3 to 11.6 kg d–1, and 16.4 to 15.0 kg d–1, respectively, as dietary NDF/NFC ratios increased.  Across all three treatments, DM and gross energy (GE) digestibility values were the highest (P<0.05) for cows at the middle and late lactation stages.  Daily CH4 emissions increased linearly (P<0.05), from 325.2 to 391.9 kg d–1, 261.0 to 399.8 kg d–1, and 241.8 to 390.6 kg d–1, respectively, as dietary NDF/NFC ratios increased during the early, middle, and late stages of lactation.  CH4 emissions expressed per unit of metabolic body weight, DM intake, NDF intake, or fat-corrected milk yield increased with increasing dietary NDF/NFC ratios.  In addition, CH4 emissions expressed per unit of GE intake increased significantly (P<0.05), from 4.87 to 8.12%, 5.16 to 9.25%, and 5.06 to 8.17% respectively, as dietary NDF/NFC ratios increased during the early, middle, and late lactation stages.  The modelling results showed that the equation using DM intake as the single variable yielded a greater R2 than equations using other dietary or milk production variables.  When data obtained from each lactation stage were combined, DM intake remained a better predictor of CH4 emissions (R2=0.786, P=0.026) than any other variables tested.  Compared to the prediction equations developed herein, previously published equations had a greater root mean square prediction error, reflecting their inability to predict CH4 emissions for Chinese Holstein dairy cows accurately.  The quantification of CH4 production by lactating dairy cows under Chinese production systems and the development of associated prediction equations will help  establish regional or national CH4 inventories and improve mitigation approaches to dairy production.

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    Effects of dietary amylose to amylopectin ratio on growth performance, carcass quality characteristics and meat fatty acids in Chinese Qinchuan cattle
    PIAO Min-yu, HU Feng-ming, KONG Fan-lin, LIU Yun-long, WANG Shuo, CUI Kai, SUN Tao, DIAO Qi-yu, TU Yan
    2021, 20 (12): 3256-2169.   DOI: 10.1016/S2095-3119(20)63576-6
    Abstract134)      PDF in ScienceDirect      
    This study evaluated the effects of the dietary starch amylose/amylopectin ratio on growth performance, rumen fermentation and blood parameters, carcass characteristics and marbling score, and meat fatty acid profiles and transcriptional changes in the genes involved in the gluconeogenesis pathway in Chinese Qinchuan cattle.  Forty-five cattle were randomly divided into three groups.  The bulls were fed a control diet (middle amylose/amylopectin ratio=0.47) or diets with either waxy corn starch (WS) inclusion (low amylose/amylopectin ratio=0.23) or pea starch (PS) inclusion (high amylose/amylopectin ratio=0.60) for 90 days.  The bulls were individually allowed to receive the diets at the daily amount of at least 2.1% of their individual BW twice daily.  The bulls were weighed at 45-day intervals, and blood and rumen fluid samples were also collected at 45-day intervals.  The bulls were slaughtered and longissimus thoracis (LT) samples were collected for meat quality measurements.  Compared with PS, the average daily gain (ADG) and feed efficiency in control and WS were increased (P<0.05) during d 0 to 45.  However, the feed efficiency in PS was increased (P<0.05) compared with the control and WS during d 46 to 90.  During the whole feeding trial, the ADG in control and WS showed trends that were higher (0.05<P<0.1) than that of PS, while other growth performance measures and feed intake did not differ (P>0.05) among the three groups.  Compared with PS, the serum insulin concentration in WS was increased (P<0.05) at d 45, but not at d 90.  Compared with control and WS, the serum SOD and T-AOC concentrations in PS were increased (P<0.05) at d 45, but not at d 90.  Compared with control, the rumen microbial crude protein contents in WS and PS were increased (P<0.05) at d 0, while those of control and WS were higher (P<0.05) than that of PS at d 45, but not at d 90.  Compared with PS, the backfat thickness in control and WS were increased (P<0.05), however, the marbling score and expression of genes related to the gluconeogenesis pathway in liver of the three groups did not differ (P>0.05).  Chemical and physio-chemical compositions of LT did not differ (P>0.05) among the three groups.  In conclusion, diets with low or middle amylose/amylopectin ratios increased the backfat thickness, and tended to improve ADG, but had no effect on other carcass characteristics, fat content in the LT, or the expression of hepatic genes related to the gluconeogenesis pathway in Chinese Qinchuan cattle. 
    Keywords: 
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    Recent advances in nutrient requirements of meat-type sheep in China: A review
    MA Tao, DENG Kai-dong, TU Yan, ZHANG Nai-feng, ZHAO Qi-nan, LI Chang-qing, JIN Hai, DIAO Qi-yu
    2022, 21 (1): 1-14.   DOI: 10.1016/S2095-3119(21)63625-0
    Abstract231)      PDF in ScienceDirect      
    China has the world’s largest sheep flock and the largest producer of sheep meat by far.  However, the nutrient requirements have not been systemically studied and there is a lack of knowledge of nutrient requirement for meat-type sheep in China.  Since 2008, the nutrient requirements of meat-type sheep in China has been systematically investigated.  In this review, we introduced the history of studies of nutrient requirements of meat-type sheep in China, summarized the recent advances in nutrient requirements of meat-type sheep, and highlighted the future directions of researches on nutrient requirements of meat-type sheep in China.
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    Recent advances in immunocastration in sheep and goat and its animal welfare benefits: A review
    ZENG Fan-mei, DING Yi, Teketay WASSIE, JING Hai-jing, Sohail AHMED, LIU Gui-qiong, JIANG Xun-ping
    2022, 21 (2): 299-309.   DOI: 10.1016/S2095-3119(21)63670-5
    Abstract236)      PDF in ScienceDirect      
    Castration of male animals is a common practice in the meat industry aimed at reducing aggressive behavior, preventing unpleasant flavor, and controlling undesirable breeding.  For many years, mechanical castration and surgical castration have been practiced to sterilize the animals.  However, these castration methods are not humane because of the associated risk of death, pain, and stress.  Recently, immunocastration targeting the hypothalamic-pituitary-gonadal axis (HPG) axis has been reported as an animal-friendly approach that circumvents many of the concerns with conventional castration, and suggested by researches as an alternative to surgical castration.  However, there is no compilation of updated information on the use of immunocastration in sheep and goats.  Therefore, this review aims to summarize the developmental process from traditional surgical castration to immunocastration and to screen the process of immune targets.  It also compares the respective advantages and disadvantages of traditional castration technologies and immunocastration, in particular including analyses in the characteristics, features application and welfare benefits of immunocastration in sheep and goats were also analyzed.
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    Dynamic change of fungal community in the gastrointestinal tract of growing lambs
    YIN Xue-jiao, JI Shou-kun, DUAN Chun-hui, TIAN Pei-zhi, JU Si-si, YAN Hui, ZHANG Ying-jie, LIU Yue-qin
    2022, 21 (11): 3314-3328.   DOI: 10.1016/j.jia.2022.08.092
    Abstract198)      PDF in ScienceDirect      

    Although fungal communities in the gastrointestinal tract have a significant role in animal health and performance, their dynamics within the tract are not well known.  Thus, this study investigated fungal community dynamics in the rumen and rectum of lambs from birth to 4 mon of age by using IT1S rDNA sequencing technology together with the RandomForest approach to determine age-related changes in the fungal ecology.  The results indicated that gastrointestinal fungal community composition, diversity, and abundance altered (P<0.05) with the increasing age of the lambs.  Two phyla, Ascomycota and Basidiomycota, dominated the samples.  Similarity within age groups of the rumen fungi increased sharply after 45 days of age, while the similarity increased (P<0.05) significantly after 60 days of age in the rectum.  The age-related genera, Acremonium, Microascus, Valsonectria, Myrmecridium, Scopulariopsis, Myrothecium, Saccharomyces, and Stephanonectria, were presented in both ruminal and rectal communities, and their changes in relative abundance were consistent at both sites.  The principal coordinates analysis showed significant differences (P<0.05) between the fungal communities in the rumen and rectum.  Our findings demonstrate that both the age of lambs and the gastrointestinal tract region can affect the composition of these fungal communities, and this provides new insight and directions for future studies in this research area.

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    Long term effects of artificial rearing before weaning on the growth performance, ruminal microbiota and fermentation of fattening lambs
    HUANG Wen-qin, CUI Kai, HAN Yong, CHAI Jian-min, WANG Shi-qin, LÜ Xiao-kang, DIAO Qi-yu, ZHANG Nai-feng
    2022, 21 (4): 1146-1160.   DOI: 10.1016/S2095-3119(21)63763-2
    Abstract134)      PDF in ScienceDirect      
    Early life intervention is important to shape the gut microbiome profiles of adult animals due to the tremendous alteration of diet components.  Nevertheless, there is still no unified understanding about its long-term effects in lambs.  In this study, sixty 20-day-old lambs were assigned into ewe-rearing (ER) and artificial-rearing (AR) treatments to evaluate the effects of AR strategy on ruminal microbiota, fermentation, and morphology of pre-weaning lambs (from 20 to 60 days of age) and its long-term effects in the fattening stage (from 61 to 180 days of age).  During the pre-weaning stage, ER lambs were breastfed and supplemented starter, while AR lambs were artificially fed with milk replacer and starter.  During the fattening stage, all lambs in both treatments were fed with the same fattening diets.  At 60, 120 and 180 days of age, 6 lambs from each group were slaughtered to collect rumen content and tissue samples.  Compared with ER lambs, the dry matter feed intakes of AR lambs increased (P<0.05) from 20 to 180 days of age, companying an increased average daily gain (ADG) from 61 to 120 days of age (P<0.05) and from 121 to 180 days of age (0.05<P<0.1).  Although there was no difference in short-chain fatty acid (SCFA, including acetate, propionate, and butyrate) between treatments before weaning (P>0.05), it was higher (P<0.05) in AR lambs compared with ER lambs at the fattening stage.  The rumen keratin layer of AR lambs was thinner (P<0.05) than that of ER lambs.  Along with lamb growth from 60 to 180 days of age, the differences in rumen bacterial diversity between AR and ER treatments grew more distinct (P<0.05).  Compared with ER lambs, AR lambs increased (P<0.05) rumen bacteria abundance, such as phylum Spirochaetes and genus Treponema at 60 days of age, phylum Actinobacteria and genus Succiniclasticum at 120 days of age, and phylum Proteobacteria at 180 days of age, but decreased genus Selenomonas from 60 to 180 days of age, and Anaerovibrio at 180 days of age.  In summary, the early interventions before weaning could improve dry matter feed intake of lambs, which triggered robust rumen development and produced positive long-term effects on rumen fermentation and noticeable weight gain of fattening lambs.  It suggests that the artificial rearing strategy is effective in improving rumen fermentation and microbial maturity of intensive fattening lambs.
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    Long-term effect of subacute ruminal acidosis on the morphology and function of rumen epithelial barrier in lactating goats
    HU Hong-lian, YANG Shu-qing, CHENG Meng, SONG Li-wen, XU Ming, GAO Min, YU Zhong-tang
    2022, 21 (11): 3302-3313.   DOI: 10.1016/j.jia.2022.08.087
    Abstract136)      PDF in ScienceDirect      

    Grain-induced subacute ruminal acidosis (SARA) impairs rumen epithelial barrier function, but it is yet to be determined if SARA can cause persistent damage to the morphology and function of the rumen epithelial barrier.  The objective of the present study was to investigate if SARA has persistent effects on the morphological structure and permeability of ruminal epithelium and the expression of the genes involved in epithelial barrier function using a lactating goat model.  Twelve mid-lactating Saanen goats with rumen cannulas were randomly assigned to 1 of 2 groups: control group (Ctrl, n=4) fed a basal diet with a non-fiber carbohydrate (NFC) to neutral detergent fiber (NDF) ratio of 1.40, and SARA group (SARA, n=8) fed the same basal diet but with increasing NFC to NDF ratio from 1.4 to 1.79, 2.31, and 3.23 overtime to induce SARA.  At the end of the SARA challenge (post-SARA), 4 goats were randomly selected from the SARA group and fed only hay mixture ad libitum for another 4 weeks to allow for restitution (post-SARA).  Ruminal pH was continuously recorded to monitor the severity of SARA.  Samples of the ventral ruminal epithelium were collected after slaughter to examine the structural and functional changes of the ruminal epithelium using transmission electron microscopy (TEM), Ussing chambers, qRT-PCR, and Western bolt analyses.  Compared with the Ctrl group, ruminal papilla length, width, surface area and thickness of stratum corneum increased (P<0.05), while stratum spinosum and basale thickness, and total depth of the epithelium decreased (P<0.05) in the SARA group.  These changes diminished or tended to return to the levels of the Ctrl group in the post-SARA group (P>0.05).  The SARA challenge also decreased cellular junction and widened the intercellular space between epithelial cells.  Rumen transepithelial short-circuit current (Isc), tissue conductance (Gt), and mucosa-to-serosa flux of paracellular horseradish peroxidase (HRP) all increased (P<0.05) both in the SARA and post-SARA groups, which indicates that SARA can induce a sustained increase in epithelial permeability and barrier dysfunction.  Moreover, the mRNA and protein expressions of CLDN1, OCLN and ZO-1 were down-regulated (P<0.01) in both the SARA and post-SARA groups.  The results of this study showed that SARA could result in sustained epithelial barrier dysfunction, at both structural and functional levels, which is associated with decreased expression of rumen epithelial tight junction proteins, and the restitution of rumen epithelial barrier function is slower than that of its morphology.

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