Effects of antibiotic-free diet and stocking density on male broilers reared to 35 days of age. Part 2: Feeding and drinking behaviors of broilers

Authors: LI, G - Mississippi State University; ZHAO, Y - Mississippi State University; Purswell, Joseph - Jody; CHESSER, G - Mississippi State University; LOWE, J - Mississippi State University; WU, T - Mississippi State University

Submitted to: Journal of Applied Poultry Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/20/2020
Publication Date: 3/20/2020
Citation: Li, G., Zhao, Y., Purswell, J.L., Chesser, G.D., Lowe, J.W., Wu, T. 2020. Effects of antibiotic-free diet and stocking density on male broilers reared to 35 days of age. Part 2: Feeding and drinking behaviors of broilers. Journal of Applied Poultry Research. 29(2):391-401. https://doi.org/10.1016/j.japr.2020.01.002.
DOI: https://doi.org/10.1016/j.japr.2020.01.002

Interpretive Summary: As a result of increasing concerns regarding antimicrobial resistance, broiler producers have reduced or eliminated the use of antimicrobials as growth promoters. The reduction of antimicrobials has required a renewed focus on flock husbandry and management to optimize the rearing environment to improve flock productivity and welfare. Stocking density is a critical management factor with significant economic consequences for broiler producers, thus optimizing stocking density for antibiotic free production is paramount to ensure competitiveness and economic sustainability. The objective of this study was to investigate broiler feeding and drinking behaviors with conventional or antibiotic free diets under four stocking densities (27, 29, 33, and 39 kg·m-2). The results show that feeding and drinking behaviors of broilers were significantly affected by diet, density, and their interaction. Feeding time (min·bird-1·d-1) were reduced for antibiotic free diets and decreased with increasing stocking density. It is concluded that behavioral responses of broilers varied at different diets and SDs and feed availability may need adjustment under different rearing programs.

Technical Abstract: The U.S. broiler industry is trending towards antibiotic-free (ABF) production because of increasing concerns on antimicrobial resistance in human medicinal treatment. Baseline behavioral responses of male broilers on ABF diet and management strategies remain addressed to sustain ABF production. The objective of this study was to investigate broiler feeding and drinking behaviors with two diets [antibiotic growth-promoting (AGP) vs. ABF] and at 4 stocking densities (SD, 27, 29, 33, and 39 kg·m-2, or ‘27SD’, ‘29SD’, ‘33SD’, and ‘39SD’, respectively). The AGP diet contained two additives, i.e. salinomycin and bacitracin, while the ABF diet did not contain any antibiotics. The treatment combinations of diet and SD were randomly assigned to 16 identical pens. Resource allowances in pens varied from 4-5 birds per feeding slot and 11-12 birds per nipple drinker. Behaviors of 15 randomly selected male broilers in each pen were monitored by an ultra-high frequency radio frequency identification system. The results show that feeding and drinking behaviors of broilers were significantly affected by diet, SD, and their interaction. Feeding time (min·bird-1·d-1) were 85.1±1.5 with AGP and 62.7±1.5 with ABF; and were 79.9±2.2 at 27SD, 78.3±2.2 at 29SD, 68.9±2.2 at 33SD, and 68.6±2.2 at 39SD. Drinking time (min·bird-1·d-1) were 28.4±0.6 with AGP and 26.6±0.6 with ABF; and were 30.1±0.9 at 27SD, 25.7±0.9 at 29SD, 25.3±0.9 at 33SD, and 28.9±0.9 at 39SD. It is concluded that behavioral responses of broilers varied at different diets and SDs, thus resource allowances need to be adjusted accordingly to optimize production efficiency.