Age-related effects of feeder space availability on welfare of broilers reared to 56 days of age1 Part 1: Biochemical, enzymatical, and electrolytes variables

Authors: Olanrewaju, Hammed; Purswell, Joseph - Jody; Collier, Stephanie; BRANTON, SCOTT - Retired ARS Employee

Submitted to: Journal of Applied Animal Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/27/2021
Publication Date: 2/12/2022
Citation: Olanrewaju, H.A., Purswell, J.L., Collier, S.D., Branton, S.L. 2022. Age-related effects of feeder space availability on welfare of broilers reared to 56 days of age1 Part 1: Biochemical, enzymatical, and electrolytes variables. Journal of Applied Animal Research. 31:3. https://doi.org/10.1016/j.japr.2022.100281.
DOI: https://doi.org/10.1016/j.japr.2022.100281

Interpretive Summary: In adequate feeder space availability for livestock in a limited environment affect free access to water causing in elevated hormonal stress secretion and injuries, thereby affecting production performance and animals’ welfare. Currently, consumers perceive feeder space availability to be one of the most important factors that affect animal welfare and the application of optimal welfare standards with adequate feeder space availability is believed to result in a higher product quality. In each trial of 2 trials, we investigated the effects of four different feeder space treatments on welfare of broiler chickens reared to 56 days of age on biochemical, enzymatical, and electrolytes parameters to ensure the health and welfare of broilers. Results show that only UA was affected by feeder space. However, age had significant effects on most examined variables. Plasma corticosterone and glucose were not affected by feeder space and age, indicating absence of physiological stress. The results are in broad agreement with those reported in the literature and contribute to our knowledge of blood metabolites and homeostatic variation in developing broilers. In conclusion, expanding feeder allowance does not enhance welfare of broilers reared to 56 days of age.

Technical Abstract: Consumer concern is about rapid growth and increased production efficiency is perceived to negatively impact the welfare of the animal. Changes in the levels of various plasma biochemistry and enzyme activity biomarkers are indicators of internal organs health and overall systemic homeostasis. This study investigated the effects of feeder space availability on welfare of broiler chickens reared to 56 days of age on biochemical, enzymatical, and electrolytes parameters. In each study, a total of 1440 1-d-old chicks (straight-run) were obtained from a commercial hatchery. Chicks were equally and randomly allocated to 32 pens based on feeder space treatment. Treatments were four different feeder space allocations: 2.3 (Single feeder), 2.30, 4.60, and 6.90 cm/bird, while a total of three feeders were used to achieve 6.90 cm/bird. To maintain uniform bird:feeder floor space, three feeders were installed in each pen, except for the single feeder pen. Blood samples (3 ml) were collected from the brachial wing vein of 3 birds per pen on d 27 and 55. The collected blood samples were centrifuged to separate the plasma and used to determine the electrolytes levels, concentration of biochemical (ALB, TBILI, BUN, CREAT, TP, UA, CHOL, LDL-C, HDL, TRIG, GLUC) parameters and enzyme (ALT, ALP, AMYL, AST, CK, GGT, LDH, LIP) activities using an ACE-AXCEL automatic analyzer. Results show that only UA was affected by feeder space. However, age had significant effects on most examined variables. Plasma corticosterone and glucose were not affected by feeder space and age, indicating absence of physiological stress. The results are in broad agreement with those reported in the literature and contribute to our knowledge of blood metabolites and homeostatic variation in developing broilers. In conclusion, expanding feeder allowance does not enhance welfare of broilers reared to 56 days of age.