The present study aimed at evaluating the effect of adding a commercial multi-enzyme complex to conventional and alternative broiler diets on the immune response and occurrence of lesions in the intestinal mucosa. In total, 900 male broiler chicks were distributed according to a completely randomized design, with six treatments of six replicates each. Two control diets were formulated: one with conventional feedstuffs (T1), based on corn and soybean meal, and one with alternative feedstuffs (T4), containing corn, millet, and soybean, canola and sunflower meals. Based on these diets, other four were prepared with reduced metabolizable energy, digestible amino acids, calcium and available phosphorus levels and the addition (T3 and T6) or not (T2 and T5) of a multi-enzyme complex. Broilers fed diets based on conventional feedstuffs had higher levels of defense cells compared with those fed diets that included millet with canola and sunflower meals. On the other hand, the use of enzymes in conventional or alternative diets decreased the number of these cells in the ileal mucosa.

The objective of this study was to evaluate the influence of methionine sources (DL-methionine 99% powder (DLM) or methionine hydroxy analog liquid 88% (HMTBA)), arginine:lysine (Arg:Lys) ratio and sodium chloride (NaCl) content in the diet of broilers on their performance, carcass yield, serum biochemistry, duodenal mucosal morphology, and immune response. Birds were kept under high temperature conditions during the grower phase and were inoculated or not with an antigen. The use of HMTBA promoted better live performance and carcass yield than the use of DLM. Diets with 1.05 Arg:Lys ratio resulted in better live performance, higher carcass and breast meat yields, longer villi, shallower crypts, and stronger immune response when broilers were challenged than the 1.40 ratio. The dietary supplementation of 6.0 g NaCl/kg promoted better growth performance and carcass weight than 2.0 g NaCl/kg. There was no influence of the different methionine sources or NaCl concentrations on any evaluated intestinal morphology parameter or immune response, nor of any interactions between these sources of variation.

A study with 2,400 broilers was carried out to compare the effect of the use of mannanoligosaccharides, Saccharomyces cerevisiae cell wall or growth promoter (Olaquindox) in the diet on broiler. Diets were based on corn and soybean meal. A completely randomized experimental design was used, and the obtained data were evaluated by analysis of variance and test of Tukey at a level of 5%. The following parameters were measured: feed intake, daily weight gain, feed conversion ratio, and mortality. It was concluded that the effect of the inclusion of mannanoligosaccharides in the diet on the studied parameters was significantly higher as compared to the inclusion of cell wall or to the control diet, but the effect was not different as compared to the inclusion of growth promoter.