Sweet potato flour (Ipomoea batatas) as natural antioxidant on carcass yield and meat physicochemical characteristics of Creole chickens of Mexico and Cobb 500.

Antioxidants are considered functional additives against oxidative stress since they avoid nutritional decline in the meat. The main objective of the present study is to evaluate the effect of sweet potato flour (SPF) as a natural antioxidant on carcass yield and physicochemical characteristics of Creole chickens of Mexico (CChM) and Cobb 500 broilers. In total, 210 chickens (105 CChM and 105 Cobb 500 chickens) were randomly assigned to three treatments: 0, 500, and 1000 mg of SPF kg-1 of feed. The Cobb 500 chickens showed higher carcass yield (hot and cold), breast, and breast fillet, whereas the CChM had higher thigh yield (P ≤ 0.05). The yield on the previously mentioned variables was not affected by the inclusion levels of SPF. The initial pH differed because of the effect of the chicken's genotype and the addition of SPF, which was higher on Cobb 500 chicken and on those that were not supplemented with SPF. The birds' skin that consumed SPF presented higher yellowness after 24 h (P ≤ 0.05). CChM manifested a higher dry matter and protein content and a lower content of ash and fat (P ≤ 0.05). In conclusion, Cobb 500 chickens present a higher carcass yield and its components, in addition to a less acid pH; however, CChM offer a higher nutritional contribution, whereas the 500 and 1000 mg addition of SPF increases the skin yellowness, which makes it an alterorganic as a pigment on broiler chicken production.

Prevention of suckling improves postpartum reproductive responses to hormone treatments in Pelibuey ewes.

To determine the effects of suckling on postpartum (pp) reproductive efficiency in Pelibuey ewes, two experiments were performed. In Experiment 1, 112 ewes were randomly assigned to one of two groups at parturition: Without restriction of suckling (WRS) 24 h day(-1) for 60 days (n=56), and Weaned Ewes (WE), weaned at 40 days pp (n=56). On Day 30 pp, all ewes were given Prostaglandin (PGF2alpha) and one of four treatments (n=14): T1, intravaginal progestagen (FGA; 40 mg) for 12 days from day 30 pp+equine chorionic gonadotropin (eCG; 300 UI) until 2 days before removing FGA; T2, FGA was applied for 12 days; T3, a second application of PGF2alpha was given on day 40 pp+eCG on the same day; T4, a second injection of PGF2alpha was applied on day 40 pp only. In all the analyzed characteristics, the best results were obtained in WE. Within the WE group, the best treatment (P<0.05) was T1 with 85.7% of the ewes in oestrus, 71.4% pregnant and a prolificacy of 1.9. Within the WRS group the best results were observed in T1. In both groups, the lowest results (P<0.05) were obtained in T4. In Experiment 2, 75 ewes were randomly assigned to one of three groups (n=25) immediately after parturition: Group 1, Without restriction of suckling (WRS, as in Experiment 1); Group 2, with restriction of suckling (RS; suckling for 30 min day(-1)); Group 3, Early Weaning (EW: at 7 days pp). All ewes were given PGF2alpha at 30 days pp and the same hormonal treatment, FGA for 12 days+PGF2alpha and eCG 2 days before removing FGA. No differences were observed (P>0.05) between RS and EW for the presentation of oestrus (96% vs. 92%), pregnancy (72% vs. 76%) or prolificacy (1.9 vs. 1.9), although group WRS did not perform (P<0.05) as well as groups RS and EW for any measure of performance. In conclusion, the combination of hormonal treatment (FGA plus eCG) with weaning at 7 or 40 days pp, or restricted suckling, improves postpartum reproductive efficiency in Pelibuey ewes, demonstrating the inhibitory role of suckling on postpartum reproduction in this breed.