Pakistan is an agro-livestock based economy with a poultry share of 55% of the total agricultural GDP (21%). The environment in Pakistan remains hot and humid during July to August, which renders the survival of poultry critical during these months, as birds are more susceptible to changing environments than other domestic animals. Heat stress is a combination of high environmental temperature and humidity, hindering proper thermoregulatory processes. It diminishes immunity, feed intake, weight gain, egg production, number of chicks per hen, hatchability of fertile eggs, egg and carcass quality, mineral balance, and increases panting and mortality and affects semen quality and fertility in male birds. Ascorbic acid (vitamin C), a white crystalline compound (also known as L-ascorbic acid) is primarily synthesised in the chicken by the kidneys, however, during heat stress, endogenous ascorbic acid becomes insufficient to meet the bird's requirements. Vitamin C ameliorates heat stress induced problems such as poor immunity, feed intake, weight gain, oxidative stress, rectal and body temperature, fertility and semen quality, carcass weight and mortality in birds.

Antioxidant vitamins have been reported to be associated with an improvement in blood lipid profiles, but results are not consistent. The present study was designed to determine whether long-term vitamin C supplementation could alter serum lipid concentrations in subjects who completed a 5-year population-based double-blind intervention trial. A total of 439 Japanese subjects with atrophic gastritis initially participated in the trial using vitamin C and β-carotene to prevent gastric cancer. Before and upon early termination of β-carotene supplementation, 134 subjects dropped out of the trial; finally, 161 subjects assigned to the high-dose group (500 mg vitamin C/d) and 144 subjects assigned to the low-dose group (50 mg vitamin C/d) were studied. No favourable effect of vitamin C supplementation on serum concentrations of total cholesterol, HDL- and LDL-cholesterol, and triacylglycerol was observed, although high-dose vitamin C supplementation increased serum vitamin C concentrations substantially. Among women, the mean change in serum triacylglycerol decreased (−0·12 mmol/l, 95 % CI −0·32, 0·09) in the high-dose group, but increased (+0·12 mmol/l, 95 % CI 0·03, 0·22) in the low-dose group. In addition, the mean change in serum triacylglycerol among women with hypertriacylglycerolaemia was statistically significant (−1·21, 95 % CI −2·38, −0·05) after high-dose vitamin C supplementation. The 5-year vitamin C supplementation had no markedly favourable effects on the serum lipid and lipoprotein profile. However, our present results do not preclude the possibility that vitamin C supplementation may decrease triacylglycerol concentrations among women with hypertriacylglycerolaemia.