Effects of prebiotic, protein level, and stocking density on performance, immunity, and stress indicators of broilers

Abstract

An experiment was conducted to determine the effects of period on the performance, immunity, and some stress indicators of broilers fed 2 levels of protein and stocked at a normal or high stocking density. Experimental treatments consisted of a 2 × 2 × 2 factorial arrangement with 2 levels of prebiotic (with or without prebiotic), 2 levels of dietary CP [NRC-recommended or low CP level (85% of NRC-recommended level)], and 2 levels of stocking density (10 birds/m(2) as the normal density or 16 birds/m(2) as the high density), for a total of 8 treatments. Each treatment had 5 replicates (cages). Birds were reared in 3-tiered battery cages with wire floors in an open-sided housing system under natural tropical conditions. Housing and general management practices were similar for all treatment groups. Starter and finisher diets in mash form were fed from 1 to 21 d and 22 to 42 d of age, respectively. Supplementation with a prebiotic had no significant effect on performance, immunity, and stress indicators (blood glucose, cholesterol, corticosterone, and heterophil:lymphocyte ratio). Protein level significantly influenced broiler performance but did not affect immunity or stress indicators (except for cholesterol level). The normal stocking density resulted in better FCR and also higher antibody titer against Newcastle disease compared with the high stocking density. However, density had no significant effect on blood levels of glucose, cholesterol, corticosterone, and the heterophil:lymphocyte ratio. Significant interactions between protein level and stocking density were observed for BW gain and final BW. The results indicated that, under the conditions of this experiment, dietary addition of a prebiotic had no significant effect on the performance, immunity, and stress indicators of broilers.

Effect of mannan-oligosaccharides (MOS) supplementation on performance, immunity and HSP70 gene expression in broiler chicken during hot-dry summer

“…The results are in accordance with Sohail et al (2013) and Huang et al (2007). Stress reduces the weight of lymphoid organs so it could be postulated that MOS supplementation reduces the heat stress in broilers leading to higher lymphoid organ weight (Houshmand et al 2012). This improved immunity may be due to improved intestinal absorption of some minerals such as Zn, Cu and Se.…”

“…Dietary supplementation of MOS helps to stabilizes corticosterone level and reduced some of the detrimental effects of heat stress (Sohail et al 2012;Houshmand et al 2012). High environmental temperatures, results in activation of the hypothalamic-pituitary-adrenal axis which leads to elevated a plasma corticosterone concentration, causing deleterious effect (Munck et al 1984).…”

Effects of prebiotic supplementation on growth performance, slaughter performance, growth of internal organs and small intestine and serum biochemical parameters of broilers

“…A large number of experiments were carried out to investigate the effects of prebiotic supplementation on growth performance. Some researchers reported that the prebiotic supplementation had no effect on growth performance (Lima et al 2003;Li & Zhang 2007;Houshmand et al 2012), however, some other researchers held opposite views (Yeo & Kim 1997;Mateova et al 2008;Wang & Gu 2010), which were similar to the current experiment. Many researches show that prebiotic in the intestine of animals can grow and reproduce and produce a variety of nutrients such as vitamins, amino acid, some factors of promoting growth, and so on.…”

Overcrowding stress decreases macrophage activity and increasesSalmonellaEnteritidis invasion in broiler chickens

“…Mortality, leg problems, susceptibility to diseases and behavioural changes were related to stress conditions from overcrowding (Estevez, 2007). Few authors have considered and analysed the effects of overcrowding on the immune system activity of chickens (Dafwang et al, 1987;Heckert et al, 2002;Houshmand et al, 2012). Heckert et al (2002) showed that high stocking densities in broiler chickens decreased the relative weight of the bursa of Fabricius, one of the most important lymphoid organs of chickens, and they related this finding to possible immunosuppression.…”