Age-related effects of feeder space availability on welfare of broilers reared to 56 days of age part 1: biochemical, enzymatical, and electrolyte variables

Abstract

SUMMARY: Consumer concern about rapid growth and increased production efficiency is perceived to negatively impact the welfare of the animal. This study investigated the effects of feeder space availability on welfare of broiler chickens reared to 56 d of age on biochemical, enzymatical, and electrolyte parameters. The study was a randomized complete block design. In each of the 2 trials, a total of 1,440 one-day-old Ross × Ross 708 chicks (straight-run) were obtained from a commercial hatchery. Chicks were equally and randomly allocated to 32 pens based on feeder space treatment. The 4 feeder space treatments were 2.3 cm/bird with one feeder per pen and 2.3, 4.6, and 6.9 cm/bird with 3 feeders per pen and retain uniform bird:feeder floor space, 3 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 for plasma to determine the electrolyte levels, biochemical concentrations, and enzyme activities. Results show that only uric acid was affected by feeder space while 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. In conclusion, expanding feeder allowance does not enhance welfare of broilers reared to 56 d of age.

Keywords

• feeder-space
• enzyme
• biochemistry
• broilers
• welfare