Effect of microbial probiotics on the performance of broiler chicks under normal or heat stress conditions. 1 - Lactobacillus or Pediococcus.

Abstract

A total of 300 one-day-old Arbor Acres broiler chicks were randomly distributed into three equal groups of 100 birds each with two replicates. The chicks were fed a commercial diet or inoculated with either Lactobacillus or Pediococcus concentrate. At 35 days of age, each group was divided into two equal sub-groups, the first was kept under normal conditions (24°C) while the second sub-group was exposed for 6 days to heat stress (38°C) for 3 h daily from 35 to 40 days of age. The feed additives increased (P0.05) the liveweight, weight gain, feed consumption and improved the feed conversion of chicks exposed to normal temperature and heat stress. Total protein, as well as albumin and globulin fraction, glucose and triiodothyronine (T3) of plasma were also increased. Whereas, mortality rate, plasma cholesterol and total lipids values were reduced (P0.05). However, creatinine, GPT and GOT enzymes, respiration rates and body temperatures were not affected. Furthermore, there were significant decreases (P0.05) in the pH of the intestines (duodenum, jejunum, ileum and caecum) and total count of some pathogenic bacteria (Escherichia coli and Salmonella pullorum). On the other hand, there were (P0.05) decreases in body weight, weight gain, feed consumption, (T3), plasma glucose, total plasma proteins and increase in mortality rate of chicks subjected to heat stress. The probiotics used improved broiler performance, blood constituents and reduce the deleterious effects of heat stress.