Dietary omega-3 polyunsaturated fatty acid does not influence the intestinal microbial communities of broiler chickens

The capacity for n-3 polyunsaturated fatty acids (PUFA) to improve broiler chicken growth, influ-ence the intestinal microbial communities, and modify the PUFA content of meat was studied. Male Cobb 500 chickens were fed 1 of 4 diets from hatch: con-trol (standard diet with no additives), ZnB (standard diet with added antibiotics), 2% SALmate (standard diet with 2% SALmate, which is composed of 42% fish oil and 58% starch), and 5% SALmate (standard diet with 5% SALmate). A 7-d energy metabolism study was conducted between d 15 and 22 posthatch. Birds were killed at d 25 and intestinal samples were collected to assess microbial communities by terminal restriction fragment length polymorphism and Lactobacillus PCR-denaturing gradient gel electrophoresis. Diet did not affect BW, feed intake, feed conversion, or ileal digest-ible energy (P > 0.05). Apparent ME was greater in ZnB-fed birds compared with all other diets (P < 0.05). Breast tissue levels of eicosapentaenoic acid, docosahexaenoic acid, docosapentaenoic acid, and total n-3 PUFA were elevated significantly in 2% SALmate- and 5% SALmate-fed chickens compared with control and ZnB diets (P < 0.05). No significant differences in over-all microbial communities were observed in the ileum or cecum as assessed by terminal RFLP (P > 0.05). Birds fed 2% SALmate had a significantly different ce-cal Lactobacillus species profile compared with birds fed the control diet (P < 0.05); however, no differences were observed in birds fed 5% SALmate compared with birds fed all other diets. In addition to the expected increase in breast tissue n-3 fatty acid levels, a low level of dietary n-3 PUFA also altered the intestinal Lactoba-cillus species profiles. However, n-3 PUFA supplemen-tation did not alter the overall microbial communities or broiler performance.