ABSTRACT. This study aimed to determine whether feeding betaine to cows elevates their production performance during summer heat stress. Thirty-two lactating Holstein cows were randomly divided into 4 groups: the control group, which received a total mixed ration (TMR), and 3 experimental groups that received TMR blended with 10 g/day (group I), 15 g/day (group II), and 20 g/day (group III) betaine for 8 weeks. Milk and blood were sampled throughout the experimental period. The average maximum and minimum air temperatures were 28.3 and 24.1°C, respectively. The average temperature-humidity index was 78.6 units. The results showed that feeding betaine to cows increased feed intake, milk yield, milk lactose, milk protein, plasma cortisol, glutathione peroxidase, superoxide dismutase, and malondialdehyde levels (P < 0.05); however, it caused HSP70 levels to decrease (P < 0.05). The milk performance of group II was significantly affected. These results indicate that supplementing betaine to the diet of dairy cows increases their milk performance and improves their antioxidant capacity; these processes help relieve the cow from heat stress. In conclusion, supplementing dairy cows with 15 g/day betaine generated the most positive influence on performance and productivity, and hence caused the greatest reduction in heat stress.

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This study was conducted to investigate the effects of in ovo feeding (IOF) of Arg solution on the hatchability, growth performance, gastrointestinal hormones, serum AA, activities of digestive enzymes, and mRNA expressions of sensing receptors and nutrient transporters in the jejunum of posthatch broilers. One thousand two hundred embryonated eggs with similar weight were randomly allocated to 5 groups consisting of 8 replicates of 40 eggs each. The 5 treatments were arranged as a noninjected control, a diluent-injected (0.75% NaCl solution) group, and Arg solution-injected groups with 0.5%, 1.0%, and 2.0% Arg, all dissolved in diluent. At 17.5 d of incubation, 0.6 mL of IOF solution was injected into the amniotic fluid of each egg of the injected groups. Results showed the hatchability of the 2% Arg group was lower (linear, = 0.025) than that of the other groups, and the BW of 21-d-old broilers increased (linear, = 0.008; quadratic, = 0.003) with increasing IOF concentration of Arg. The ADFI (linear, = 0.005; quadratic, = 0.001) and ADG (linear, = 0.010; quadratic, = 0.004) increased during d 1 to 21 with increasing IOF concentration of Arg. For 7- and 21-d-old broilers, the weights of digestive organs increased (linear, < 0.05) with increasing IOF concentrations of Arg; the greatest values were observed in the 1% Arg group. For 21-d-old broilers, IOF of the 1% Arg solution increased ( < 0.05) the concentrations of ghrelin and glucagon-like peptide 2; the activities of digestive enzymes, alkaline phosphatase, maltase, and sucrase in the jejunum; and the concentrations of serum AA of Val, Met, Ile, Leu, Arg, and Pro compared with those of the noninjected control and diluent-injected group. In ovo feeding of the 1% Arg solution also increased ( < 0.05) the mRNA expressions of jejunal sensing receptors of taste receptor type 1 members 1 and 3; the G protein-coupled receptor, class C, group 6, subtype A; nutrient transporters of solute carrier family 7, members 4, 6, and 7; sodium-glucose transporter 1; and fatty acid-binding protein 1. In conclusion, the 1% Arg solution was the appropriate injection level. In ovo feeding of the 1% Arg solution did not affect the hatchability but facilitated the release of gastrointestinal hormones, increasing the digestive and absorptive capacity and finally improving the growth performance of 21-d-old broilers. Therefore, IOF of the appropriate Arg solution could be an effective technology for regulating early nutrition supply and subsequent growth development in the poultry industry.

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