Effects of dietary fats rich in lauric and myristic acid on performance, intestinal morphology, gut microbes, and meat quality in broilers.

This study investigated the hypothesis that dietary fats rich in lauric (C12) and myristic acid (C14) increase broiler performance and that the underlying mechanism involves antimicrobial effects on gut bacteria and changes in gut morphology. One hundred eighty 1-day-old Cobb-500 broilers were allotted to 3 groups. All groups received a basal diet consisting of maize, wheat, soybean meal, and a fat source (4.5, 7.0, 7.6, and 8.0% of fat product in the diet during d 1 to 9, 10 to 17, 18 to 27, and 28 to 35, respectively) until 35 d of age. The diet of the control group contained a fat with 67% of oleic and linoleic acid and 1.4% of C12 and C14 of total fatty acids, that of the esterified lauric and myristic acid (ELA) group a fat with 33% of esterified C12 and C14 and that of the free lauric and myristic acid (FLA) group a fat with 31% of both esterified and free (1:1) C12 and C14 (6 replicates/treatment, 10 birds/replicate). Gain and feed consumption did not differ between groups, but feed:gain was lower in FLA group as compared to the control group (P < 0.05). Carcass weight, liver weight, triglyceride content of liver and muscle, and muscle cholesterol were similar between groups; however, breast muscle weight was higher in the FLA than in the control group (P < 0.05). The villus height:crypt depth ratio of the duodenal wall did not differ between groups, but in the jejunum, it was lower in the FLA group as compared to the control group (P < 0.05). DNA copy numbers of Lactobacillus, Bifidobacteria, Enterobacteria, Escherichia coli, and Campylobacter jejuni in jejunal digesta were similar among groups. The study shows that dietary fats rich in free C12 and C14 improved feed:gain and breast muscle yield, but the observed effects could not be conclusively explained based on the parameters measured. The decreased jejunal villi:crypt ratio may point to changes in gut protein or cell turnover.