Impact of Sacchromyce cerevisiae (Yeast) Supplementation in Varied Cereal-Based Broiler Starter Diets on Gut Microflora and Morphology

Abstract

The experiment investigated the effect of yeast, Saccharomyces cerevisiae (SC) on gut microflora and gut morphology integrity of broiler chickens. A total number of 324 day old Arbor Acres broilers chicks were allocated to 9 x 3 replicates pens consisting of twelve birds each. One of the nine diets consisted of wheat, maize and sorghum with 5% SC inclusion each while the other six diets are the positive and negative control (positive control- maize, wheat and sorghum with antibiotics and negative control-without SC were fed for twenty-eight days. Data on gut morphology and gut microflora from the caeca were collected. At 28 days of age, two birds per replicate that is six birds per treatment were sacrificed through cervical dislocation. Sections of ileum were cut, flushed in distilled water and fixed in 10% formalin for 48hours. The tissues were grossed and cut into smaller pieces of 3mm thick in pre labeled tissue cassette. They were processed using Automatic tissue processor. Total anaerobic counts (TAB) were determined using Fastidious Anaerobe agar (FAA) incubated at 37°C for 5 days. Enterococci counts were enumerated using Slanetz and Bartley incubated aerobically at 37°C for 48 hrs. Coliform counts were enumerated using MacConkey agar, incubated aerobically at 37°C for 24 hrs and Lactobacilli counts were determined using de Man Rogosa and Sharpe (MRS) agar, incubated anaerobically at 38°C for 48 hrs. After incubation, colonies formed on the respective media were carefully counted and calculated. Data obtained were subjected to analysis of variance and means were separated using Duncan multiple range test. Inclusion of SC in the diets had a beneficial effect on the ileum morphology resulting in a significant increase (P<0.05) in villus height of birds fed maize +SC, wheat +SC, sorghum +SC, maize +AB and sorghum +AB but crypt depth, muscular wall length (MWL), villus to crypt ratio and goblet cells number were not significantly different in the dietary treatments. Although the highest crypt, MWL, villus/ crypt ratio and goblet cells number were recorded in Maize +AB (1526.8 µm), sorghum +AB (3466.9 µm), and wheat + SC (2750.7 µm and 129) respectively. Inclusion of SC in the diets had no significant difference on the ceca digesta of broiler birds compared to the positive and negative control on Coliform, total anaerobic bacteria and Lactobacillus sp. Populations. Significant difference (P<0.05) was observed in Enterococci population. Birds on sorghum -SC were significantly higher than birds on sorghum + AB but comparable with rest of the dietary treatments. Using Saccharomyces cerevisiae (SC) as a growth supplement can enhance the growth and nutrient absorption of broiler birds through the inhibitory effect of yeast against pathogenic microorganisms.