Age-Related Changes in Serum Lipid Levels, Hepatic Morphology, Antioxidant Status, Lipid Metabolism Related Gene Expression and Enzyme Activities of Domestic Pigeon Squabs (Columba livia)

SIMPLE SUMMARY: Research on antioxidant status and lipid metabolism in pigeon squabs as meat type poultry is limited. The objective of this study was to explore the age-related changes in the antioxidant status and lipid metabolism of pigeon squabs (Columba livia). Ten squabs were randomly selected, out of 400 hatched squabs, on the following days: day of hatching (DOH) and days 7 (D7), 14 (D14), 21 (D21) post-hatch, respectively. BW, serum lipid levels, antioxidant capacity indices, lipid metabolism-related enzyme activities, lipid metabolism-related gene expression, and liver morphology were determined. Results indicated that the phase from DOH to D14 was a growth spurt, especially in the first seven days. The antioxidant capacity of squabs had a continuous decline from DOH to D14. Besides, changes regarding lipid metabolism mainly occurred in the phase from DOH to D14. The first seven days mainly showed less lipid breakdown, while the second seven days displayed more complicated lipid metabolism. The results obtained from this study suggested that, in the pigeon industry, it is better to take nutritional manipulation in squabs before D14. ABSTRACT: The objective of this study was to evaluate the age-related changes in antioxidant status and the lipid metabolism of pigeon squabs (Columba livia), by determining the BW, antioxidant indices, serum lipid levels, lipid metabolism-related enzyme activities, lipid metabolism-related gene expression, and liver morphology in squabs. Ten squabs were randomly selected and sampled on the day of hatching (DOH), days 7 (D7), 14 (D14) and 21 (D21) post-hatch, respectively. The results showed that BW of squabs increased linearly from DOH to D21. The minimum fold of BW gain was observed in the phase from D14 to D21. Serum triglyceride and free fatty acid levels displayed linear and quadratic trends as age increased, with these maximum responses in D14. Serum low-density lipoprotein cholesterol level responded to age linearly and quadratically with the minimum in D14. Serum high-density lipoprotein cholesterol level and the ratio of high-density lipoprotein cholesterol to low-density lipoprotein cholesterol increased linearly with age, whereas the very low-density lipoprotein cholesterol level decreased linearly. The activities of glutathione peroxidase, catalase, and superoxide dismutase in liver displayed linear and quadratic trends as age increased, with these minimum responses in D14. Hepatic malondialdehyde concentration responded to age linearly and quadratically, with the maximum in D14. Activities of lipoprotein lipase, hepatic lipase, and 3-hydroxy-3-methyl glutaryl coenzyme A reductase in liver responded to age linearly and quadratically, with these minimum responses in D14. Hepatic hormone-sensitive lipase activity displayed linear and quadratic trends as age increased with the maximum in D14. Hepatic acetyl CoA carboxylase activity on D14 was significantly lower than squabs on DOH and D7. Hepatic carnitine palmitoyltransferase 1 mRNA expression responded to age linearly and quadratically, with minimum response in D14. Hepatic mRNA expression of acetyl CoA carboxylase and fatty acid synthetase increased linearly with age. Hepatic Oil-Red-O staining area displayed a quadratic trend as age increased, with the maximum response in D14. In conclusion, the phase from DOH to D14 was a crucial development stage for growth, antioxidant status and lipid metabolism in pigeon squabs. The results suggest it is better to take nutritional manipulation in squabs before D14.