Betaine could help ameliorate transport associated water deprivation stress in broilers by reducing the expression of stress-related transcripts and modulating water channel activity

Abstract

This study evaluated the effects of betaine and pre-slaughter transport of broilers on meat quality, blood parameters, selected water channels (AQP) and stress-related transcripts. Ross 308 broilers (n = 336) were housed in 56-floor pens with seven replicates per treatment. In a 4 × 2 design, broilers were either supplemented with betaine in the feed (0.2%), in drinking water (1 or 2 mL/L), or un-supplemented, and then were transported for 5-min or 4-h pre-slaughter. The results revealed that broilers transported for long-distance had elevated blood glucose pre-slaughter, and their breast meat was characterised with lower initial pH, higher ultimate pH, higher 0-h post-mortem temperature, and lower water holding capacity than those transported for short-distance. Moreover, there was a two-way interaction effect between betaine and transport on the expression of brain genes (Proopiomelanocortin, AQP1, AQP4), muscle glucocorticoid receptor (GR), hepatic AQP3 and AQP9 and intestinal AQP3. Long-distance transport upregulated the relative expression of the muscle AQP9 and downregulated the hepatic GR. Furthermore, betaine in the water at 2 mL upregulated the muscle AQP9 and hepatic GR. In conclusion, betaine could ameliorate the water-deprivation stress associated with transportation by reducing the expression of stress-related transcripts and modulate water channels without improving broiler meat quality. HIGHLIGHTS Long-distance transport of broilers is stressful, as evidenced by rising blood glucose, high temperature of fresh meat, and expression of stress-related transcripts. Betaine could ameliorate the water-deprivation stress associated with transport by reducing the expression of stress-related transcripts and modulating water channels.