Comparative effects of medium-chain fatty acids or phytobiotics-based feed additives on performance, caecum microbiota, volatile fatty acid production and intestinal morphology of broilers.

Antibiotic growth promoters have been utilized in broiler nutrition to alleviate the negative effects of the pathogenic microbes to promote performance. However, after the prohibition of antibiotics because of the increasing disclosure related to public health issues, various products have been developed as alternatives. This study was carried out to determine the effects of medium-chain fatty acids (MCFAs) or phytobiotics (essential oils [EOs] and alkaloids [ALKs]), blended feed additives on the growth performance, jejunum histomorphology, and cecal microbiota of broiler chickens. A total of 765 male Ross 308 chicks were randomly distributed into 5 experimental groups, each having 9 replicates with 17 chicks. The experimental procedures were as follows: a control group without supplementation (T1); control group+ MCFAs and EOs blend (T2); control group+ different EOs blend (T3); control group+ ALK sanguinarine (T4); and control group+ EOs and ALK piperine mixture (T5). The results showed that, broilers fed with MCFAs blended with EOs had significantly greater body weight gain during overall period in comparision to the control and T3 groups. Further, only MCFAs blended with EOs group significantly improved jejnum morphology in comparison with the control group (p ≤ 0.05). Besides, the MCFAs blended with EOs group significantly elevated propionate, acetate and butyrate concentration, and decreased the concentration of branch chain fatty acids in caecum (p ≤ 0.05). The results indicated that, the combination of MCFAs and EOs seems to have improvement effects and could be preferred as an efficient feed additive in broiler production.

Does modern broilers need less energy for better growth and intestinal development?

The current study was carried out to evaluate the response of broiler chicks to dietary energy. In total 11,400 day-old Ross-308 chicks (95 males and 95 females per pen) were placed in the study for 42 days. Hatchlings were randomly distributed to 6 dietary treatments with 10 replicates. Aviagen metabolisable energy (ME) recommendation for Ross 308 was served as a positive control (PC) and other treatments were adjusted to 101.25, 98.75, 97.50, 96.25 and 95% of PC. Birds had free access to water and pellet feed. Body weight (BW), Feed intake, feed conversion ratio (FCR), carcass yield and jejunal morphometric analysis were determined per replicate. Feeding the birds with 1.25% higher ME than PC did not result in any improvement in BW, FCR, mortality and carcass parameters. Significant linear improvement was observed at starter period for BW and FCR with the reduction of dietary ME (p < 0.05). There was no significant impairment in final BW with the reduction of ME up to 5.0%. Whole period FCR reduced by 0.009, 0.022, 0.014, 0.037 points by lowering ME by 1.25, 2.5, 3.75 and 5%, respectively (linear, p < 0.05). Carcass yield, abdominal fat and pancreas weights were not significantly influenced (p > 0.05). However, significant improvement in villus height, surface area (quadratic and cubic, p < 0.05), and villus width (quadratic, p < 0.05) were observed with 2.5 and 3.75% reduction of dietary ME. Dietary treatments had no significant effect on liver haemorrhagic lesion score. The results of the current research suggest that the optimum level of dietary energy level of modern broilers may be lower than the one recommended by the primary breeders. Lowering dietary energy density up to 5% leads to 0.03 points reduction in FCR without any negative effect on BW.