This study investigated the effects of dietary arginine (Arg) supplementation, just during lactation, on sow and litter performance, plasma concentrations of metabolites and hormones, and milk yield and composition in multiparous sows.  Thirty-one sows were randomly assigned to 3 dietary treatments supplemented with 0.0 (control, n=10), 0.5% (n=10), or 1.0% (n=11) L-Arg-HCl, respectively.  Experimental diets were provided to the sows from d 3 to 21 of lactation.  Plasma and milk samples were collected at d 14 and 21 of lactation.  The average daily gain (ADG) of piglets from sows fed diets supplemented with 0.5 or 1.0% L-Arg-HCl at d 3 to 14 of lactation, were higher than that of controls (P<0.05).  Maternal supplementation with 1.0% L-Arg-HCl also increased ADG of piglets between d 3 and 21 of lactation than that of the controls (P<0.05).  There was no significant effect of supplementation on average daily feed intake (ADFI), body weight loss, and backfat thickness loss of lactating sows.  Supplementation with 0.5 or 1.0% L-Arg-HCl had a trend towards increasing milk yields and milk fat contents (0.05<P<0.10); milk protein and lactose were unchanged.  Supplementation with 1.0% L-Arg-HCl increased plasma concentrations of prolactin and insulin in sows at d 14 and 21 of lactation, and plasma concentrations of non-esterified fatty acid (NEFA), insulin-like growth factor-1 (IGF-1), and nitric oxide (NO) in sows at d 21 of lactation, when compared to the controls (P<0.05).  Supplementation with 1.0% L-Arg-HCl increased IGF-1 and spermine in milk at d 14 of lactation, relative to the controls (P<0.05).  Plasma Arg concentrations at d 14 and 21 of lactation, as well as plasma NO level and milk IGF-1 at d 21 of lactation, were increased, while plasma urea nitrogen (PUN) concentration at d 14 and 21 of lactation was decreased, by supplementation with 0.5 or 1.0% L-Arg-HCl when compared to the controls (P<0.05).  Collectively, dietary supplementation of multiparous sows with Arg, just during lactation, is beneficial for enhancing litter weight gain but the complete mechanism remains to be determined and may involve in the maternal endocrine changes and milk polyamines contents.

To investigate the effects of a synthetic isoflavone (SI) on meat quality and oxidative stability, 1 500 43-d-old Lingnan yellow male broilers were randomly assigned to five dietary treatments: diets supplemented with 0, 10, 20, 40, or 80 mg SI kg-1, fed ad libitum for a period of 3 wk. After refrigerated storage, a* value of the meat increased with dietary SI supplementation using 10 and 40 mg kg-1 level (P<0.05), L* value decreased (P<0.05), and 40 mg kg-1 increased the pH (P<0.05). Supplementation with SI, at all levels, increased water holding capacity (P<0.05) and decreased lactic acid content of meat (P<0.05). The concentration of malondialdehyde at 72 h decreased linearly (P=0.005) and quadratically (P=0.004) with increasing levels of SI. Dietary SI at 20 and 40 mg kg-1 levels enhanced total superoxide dismutase activity in meat (P<0.05). Meat pH quadratically decreased as the storage time increased (P<0.05), with the highest value at 24 h (P<0.05). Lactic acid and malondialdehyde concentrations of meat increased over time, with value at 96 h being far higher than at earlier times (P<0.05). Supplemental SI linearly and quadratically increased the mRNA abundance of glutathione peroxidase (GPX) (P=0.001 and P=0.002) and catalase (CAT) (P=0.003 and P=0.006) in breast muscle. The results from this study indicate that dietary supplementation with SI can improve meat quality during refrigerated storage by decreasing lipid peroxidation and enhancing oxidative stability and, for male broilers from 43 to 63 d of age, the optimal level of SI was 40 mg kg-1.