Effects of Nutrient Density and exogenous enzymesin Starter Diet on Performance, Intestinal Microflora, Gut Morphology and Immune Response of Broiler Chickens

Abstract

A total of 810 one-day-old, straight-run broilers were used to evaluate the effects of dietary nutrient density and feed additives included in the starter diet on their performance, intestinal microbiota, gut morphology, and immune response. A 3×3 factorial arrangement with three nutrient densities (100, 103.75 and 107.5%, as recommended) and three feed additives (no additives, 0.5 g/kg diet Maxi-Gen, and Maxi-Gen + Superzyme + Bio-Phytase at the rate of 0.5, 0.25 and 0.1 g/kg diet, respectively), fed from 1 to 10 d of age. Similar commercial corn-soy grower and finisher diets fed to all birds from 10-24 and 24-42 d of age, respectively. There was higher (p<0.05) body weight gain and lower (p<0.05) feed conversion ratio in chicks fed starter diet with 107.5% nutrient density and Maxi-Gen with or without exogenous enzymes compared with those fed control diet at 10 and 42 d of age. Lactobacilli and Bifidobacteria counts in the cecal content were increased linearly as dietary nutrient density increased in 10-d-old birds (p<0.05). Higher duodenal and jejunal villus height and villus height to crypt depth ratio (p<0.05) were measured in the birds fed the starter diets with 103.75% and 107.5% nutrient density at 5 and 10 d of age. Total anti-SRBC and IgM titers were significantly higher in the broilers fed the 107.5% nutrient density diet containing feed additives at 35 day of age. It is concluded that higher nutrient density and the inclusion of feed additives in the starter diet may improve the growth performance, gut morphology, and immune response of broiler chickens.

Effects of Low-Protein Diets and Exogenous Protease on Growth Performance, Carcass Traits, Intestinal Morphology, Cecal Volatile Fatty Acids and Serum Parameters in Broilers

“…The crypt is considered the be the villi factory, and deep crypts indicate rapid tissue turnover and a high demand for new tissue [43]. It has been reported that dietary exogenous enzymes improved the gut morphology of broiler chickens [27,39,44]. However, the results of our study contradict these reports because we found that dietary ENZ did not affect the gut morphological indices that we measured at 21 days.…”

Adding wheat and rapeseed meal to corn-soy diets affects intestinal morphology and nutrient digestibility in broilers

“…Several researchers reported that feed additives did not affect villus height (Houshmand et al, 2012) or width (Aliakbarpour et al, 2012;Fallah et al, 2013) compared with control groups. It has been reported that dietary exogenous enzymes improved the gut morphology of broiler chickens (Nabizadeh et al, 2017). However, the results of the present study indicate that the addition of dietary enzymes and thyme essential oil have similar effects on intestinal morphology.…”

Gut Micro-flora, Serum Bio-markers, and Growth Performance of Broiler Chickens Fed Supplemental Levels of Bacillus protease

“…These observations may be due to the enzyme's ability to increase the levels of available substrate for microbial fermentation which improve protein digestibility and the production of short chain fatty acids (SCFA) in the gut as a result of non-digested protein diet that become available to the gut micro-biota [31]. Nabizadeh et al [32] also reported a similar observation. It is possible that Bacillus protease supplementation resulted in the numerical multiplication of beneficial bacteria in the present study.…”

“…Changes in the intestinal micro-biota of chickens can alter the mucosal structure and thereby influence nutrient absorptive capacity [26]. Many researchers reported that increasing SCFA density causes a gradual decrease in the proliferation rate of Enterobacteria but not that of Lactobacillus, Bifidobacteria [35], [36], [32]. Contrary to the results of this study, exogenous enzymes have been reported to modulate the gut micro-biota of birds which may in turn affect the health status and the extent of digestion by the host [37].…”