Performance, carcass and meat quality of pigs submitted to immunocastration and different feeding programs.

The feed restriction of pigs aims to improve the nutrient utilization of the diet, reduce carcass fat and increase lean meat. Immunocastration is a painless, reversible technique that improves animal welfare, decreases boar taint in meat, leading to lower fat deposition and increases lean meat. This study aimed at evaluating either feeding (restricted) programs (FP) and castration categories (surgically castrated × immunocastration) in terms of pig performance, carcass traits and meat quality. Castration category and FP did not influence marbling, initial pH and drip loss in loin and ham. However, immunocastrated pigs presented lighter loins and hams with lower ultimate pH, compared to the surgically castrated pigs. The FP with lower feed volume resulted in higher ultimate pH. Immunocastrated males had a higher live weight than those surgically castrated. Also, the more the feed supply decreased, the better the feed conversion. Immunocastrates had lower carcass yields, however these pigs had their backfat thickness decreased and lean meat increased in the carcass, without affecting the loin depth.

Selenomethionine as a dietary supplement for laying hens: Impacts on lipid peroxidation and antioxidant capacity in fresh and stored eggs.

The objective of this study was to determine whether supplementing the diets of laying hens with selenomethionine (SM, 1% selenium) improves performance and egg quality. We supplemented diets with SM as follows: T0 control (without SM); T5, T10, T15, and T20 were supplemented with 5, 10, 15, and 20 mg of SM/kg of feed, respectively (equal to 0.05, 0.10, 0.15, and 0.20 mg selenium/kg of feed). T5 and T10 hens showed better feed conversion per kg of egg, percentage of laying, higher daily feed intake, and higher average egg weight. The eggs of hens supplemented with SM had lower levels of lipoperoxidation (LPO) in fresh (T15 and T20) and stored eggs (T20). Glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities, as well as total antioxidant capacity were greater in egg yolks after storage (T10; T15; T20 compared to T0). Hens supplemented with SM had elevated GPx and SOD activities and decreased oxidative reactions. PRACTICAL APPLICATIONS: Selenium has several nutraceutical properties, with beneficial effects on the health of the animal and the food produced from them (eggs, in this case). Selenomethionine supplementation in the diet of laying hens improves productive efficiency, stimulates the antioxidant system and reduces lipid peroxidation in the egg yolk. Egg-laying hens that received selenomethionine showed minimized lipid peroxidation in stored eggs, possibly improving shelf life of the eggs.

Spirulina platensis in Japanese quail feeding alters fatty acid profiles and improves egg quality: Benefits to consumers.

The aim of this study was to investigate whether microalgae in Japanese quail feed alters performance, fatty acid profiles in the eggs and egg quality. One hundred quails were distributed in four groups and five replicates of five birds per experimental group. The treatments consisted of four levels of Spirulina platensis microalgae (0%, 5%, 10%, and 15%) in the diets. We evaluated the productive performance and chemical-physical characteristics of eggs, the oxidant/antioxidant status in egg yolks, and the fatty acid profile in the diet and egg yolks. Microalgae in the diet did not influence egg production; however, it increased the yolk index as well as the color intensity of the yolk. Saturated and polyunsaturated fatty acid levels decreased in egg yolks, and monounsaturated fatty acid levels increased in the yolks. Lipid peroxidation levels were lower and total antioxidant capacity was higher in egg yolks of quails receiving microalgae in the diet. PRACTICAL APPLICATIONS: Microalgae in quail diets improves egg quality and provides benefits to consumer health, acting as an antioxidant and immune-stimulant. Microalgae in quail diets had positive effects on egg quality. This is because it reduced levels of saturated fatty acids that are undesirable, and increased monounsaturated fatty acid levels that are beneficial to the health of consumers. Finally, antioxidants increased in egg yolks, consequently reducing lipid peroxidation.

Estimation of optimal ratios of digestible phenylalanine + tyrosine, histidine, and leucine to digestible lysine for performance and breast yield in broilers.

Three experiments were carried out to estimate the optimal ratios of digestible phenylalanine + tyrosine (Phe + Tyr), histidine (His), and leucine (Leu) relative to digestible lysine (Lys) for performance and carcass criteria of Cobb-500 broilers from 8 to 17 d of age. In each experiment, 160 male chicks were allocated to a completely randomized experimental design with eight replicate pens, each receiving five dietary treatments. A common, semi-purified basal diet was formulated to meet all dietary recommendations except for those of the tested amino acids (i.e., Phe + Tyr, His, and Leu). Growth performance and carcass characteristics data were analyzed using various requirement-estimation models, including 95% of the quadratic regression, linear response plateau (LRP; i.e., stepwise regression), LRP-to-quadratic regression ratio; and quadratic broken line (QBL). Graded digestible Phe + Tyr ratios elicited a quadratic response (P < 0.05) in body weight gain and linear responses (P < 0.05) in breast and breast fillet weights. Linear effects (P < 0.05) were also observed when graded ratios of digestible His were fed for feed intake and weight gain, and quadratic responses (P < 0.05) were noted for feed conversion ratio and breast and breast fillet weights and yields. Graded Leu ratios elicited quadratic responses (P < 0.05) in feed intake, weight gain, and breast and breast fillet weight and yield. Based on growth and carcass parameters, the estimated ideal digestible ratios of Phe + Tyr, His, and Leu relative to digestible Lys were 112, 38, and 104%, respectively, for broiler chicks raised from 8 to 17 d of age.