RESUMEN
This study aims to investigate the effects of nanoparticles of zinc oxide (Nano-ZnO) supplementation on productive performance, nutrient digestibility, mineral retention, and blood biochemistry of Californian male rabbits under hot climatic conditions. A total of 100 Californian male rabbits 90 days of age (BW: 1790 ± 13 g) were randomly assigned to one of five treatment diets: Nano-ZnO at 0, 25, 50, 75, or 100 mg/kg, respectively, for 90 days. The rabbits were raised in an open house system (average ambient temperature of 39 °C, relative humidity of 30-35%, and temperature-humidity index of 33.6-34.0). Each treatment had 20 rabbits, and each rabbit was considered as a replicate. During the entire study period, there were no significant differences (P > 0.05) in BW, BW gain, feed intake, or feed conversion ratio between the treatment groups. Nano-ZnO supplementation at 25, 50, 75, and 100 mg/kg enhanced the digestibility coefficient of crude protein (CP) and ether extract (EE) considerably (quadratically, P < 0.05) when compared to the control group. In addition, when Nano-ZnO was supplemented at 25, 50, 75, and 100 mg/kg, serum levels of creatinine, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were considerably lower than the non-supplemented control group. Furthermore, when comparing the control and Nano-ZnO-fed rabbits, serum testosterone concentrations increased significantly (P < 0.05) in the treated groups. In addition, compared to the other groups, the 50 mg/kg Nano-ZnO group had the highest cecal Lactobacilli spp. count. These findings suggest that supplementing Californian male rabbits with 50 mg/kg dietary Nano-ZnO enhanced CP and EE digestibility, cecal Lactobacilli spp., as well as serum testosterone levels, and decreased serum ALT and AST levels under hot climatic conditions.
Asunto(s)
Nanopartículas , Óxido de Zinc , Animales , Masculino , Conejos , Alimentación Animal/análisis , Fenómenos Fisiológicos Nutricionales de los Animales , Dieta , Suplementos Dietéticos , Testosterona , Óxido de Zinc/farmacologíaRESUMEN
1. Two separate experiments were conducted to evaluate the efficacy of either prebiotic or synbiotic on growth performance, carcass yield, organ weights, and serum metabolic profile of broilers under hot climatic conditions. 2. In experiment 1, 150 1-d-old Ross 308 male broiler chickens were fed dietary synbiotic (Biomin® IMBO, 0, 1 or 1.5 g kg-1 of the starter diets and 0, 0.5 or 0.75 g kg-1 of the grower diets) for 6 weeks. In experiment 2, 150 1-d-old Ross 308 male broiler chickens were fed dietary prebiotic (Mannan oligosaccharide 0, 0.5 or 1 g kg-1 of the starter diets and 0, 0.25 or 0.5 g kg-1 of the grower diets) for 6 weeks. Each treatment had 10 replicates containing 5 broiler chickens each. 3. Supplementation of synbiotic at 1 or 1.5 g kg-1 feed to broiler diets during 1-21 d and 0.5 or 0.75 g kg-1 feed, respectively, during 22-42 d improved (P < 0.01) body weight gain, feed conversion ratio (FCR), and decreased (P < 0.01) abdominal fat, serum total cholesterol, and low-density lipoprotein (LDL) cholesterol levels in experiment 1. 4. Similarly, supplementation of the prebiotic at 0.5 or 1 g kg-1 in broiler diets during 1-21 d and 0.25 or 0.50 g kg-1 feed, respectively, during 22-42 d improved (P < 0.01) body weight gain, FCR, and decreased (P < 0.01) abdominal fat, serum cholesterol, and LDL-cholesterol levels in experiment 2.