Growth performance, nutrient availability and immunity responses in broiler chickens fed a commercial blend of phytogenic feed additives

Authors: PIRGOZLIEV, V - Scottish Agricultural College; MANSBRIDGE, S.C. - Harper Adams University College; ROSE, S.P - Harper Adams University College; Lillehoj, Hyun; BRAVO, D - Pancosma Sa

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/12/2018
Publication Date: 9/1/2019
Citation: Pirgozliev, V., Mansbridge, S., Rose, S., Lillehoj, H.S., Bravo, D. 2019. Growth performance, nutrient availability and immunity responses in broiler chickens fed a commercial blend of phytogenic feed additives. Poultry Science. https://doi.org/10.3382/ps/pey472.
DOI: https://doi.org/10.3382/ps/pey472

Interpretive Summary: Phytogenic feed additives (PA) in diets has been shown to improve performance and health in commercial chickens and other farm animals. Dietary supplementation of certain PA improves growth performance, improves innate immunity and host disease resistance. In this paper, ARS scientists collaborated with scientists in the EU to investigate the effects of a commercial blend of PA comprising 5 % carvacrol, 3 % cinnamaldehyde, and 2 % capsicum oleoresin on the modulation of innate immune responses of broiler chickens, their growth performance, dietary energy and nutrient availability. The results clearly showed that dietary PA supplemented diets reduced inflammation, and improved overall growth performance variables, energy and nutrient availability. This finding should provide new information on the mechanism of action of this commercial PA.

Technical Abstract: This study aimed to assess the effect of a commercial blend of phytogenic feed additives (PA), comprising 5 % carvacrol, 3 % cinnamaldehyde, and 2 % capsicum oleoresin on the modulation of innate immune responses of broiler chickens, their growth performance, dietary energy and nutrient availability. Four-hundred day-old birds were assigned to one of four dietary treatments. Two control diets based on either wheat (WC) or maize (MC) were each given with and without PA at 100 g/t. Growth performance variables including feed intake (FI), weight gain (WG) and feed conversion ratio (FCR) were recorded. Dietary N-corrected apparent metabolizable energy (MEn), dry matter retention (DMR), nitrogen retention (NR) and fat digestibility (FD) were also determined. Gene expression was determined on caecal tonsil tissue from 21d old birds. Expression of IL2, IL18, IL10 and IL17C in the caecal tonsils were upregulated (P < 0.05) in the birds fed maize based diets compared to the wheat fed birds. Feeding PA supplemented diets downregulated the expression of CD 40 LG (P < 0.001), IFNG and IL6 (P < 0.05). There was a cereal type x PA interaction (P < 0.05), as expression of IFNB was downregulated in the birds fed PA supplemented MC but not WC. However, expression of IL12B was downregulated in birds fed PA supplemented WC but there was no significant (P > 0.05) change in expression levels in birds fed maize based diet. Feeding maize based diets gave higher FI (P < 0.001) and ME (P < 0.05), but lower FCR (P < 0.05) compared to birds fed wheat-based diets. The WG and nutrient retention coefficients were not affected (P > 0.05) by cereal type. Supplementary PA improved FI (P < 0.05), WG (P < 0.001), FCR (P < 0.05), MEn (P < 0.05), MEn:GE ratio (P < 0.05) and FD (P < 0.05). In conclusion, dietary inclusion of PA improved overall growth performance variables, energy and nutrient availability and intestinal cytokine expression.