BACKGROUND: Carnitine biosynthesis needs methionine and lysine amino acids, vitamins niacin and ascorbic acid. So the usage of both L-carnitine and vitamin C may  improve the effects of only L-carnitine. OBJECTIVES: This study was carried out to investigate the effects of different levels of L-carnitine and vitamin C on the growth performance‚ body composition; blood serum parameters in Rainbow trout (Oncorhynchus mykiss) were investigated. METHODS: For this purpose, 540 fingerlings with the average weight 40±2 g were arranged in treatments including 3 vitamin C levels: zero, 500, 1000 and 2 L-carnitine levels: zero, 800 (mg/kg diet), with 3 replicates. RESULTS: Results showed weight gain, special growth rate and feed conversion ratio in the level of 500/800 vitamin C/L-carnitine had a significant increase compared to control (p<0.05). The highest and the lowest lipid content were observed in control and 1000/800vitamin C/ L-carnitine, respectively (p<0.05). The highest protein content was observed in 500/800 vitamin C/L-carnitine (p<0.05). Cholesterol and glucose showed a significant decrease in 500/800 vitamin C/L-carnitine. It was observed that 1000/800 vitamin C/L-carnitine caused significant decrease in blood triglycerides (p<0.05). CONCLUSIONS: Finally, it was determined that using vitamin C 500 and L-carnitine 800 mg/kg diet caused some improvement in growth performance with no  negative effects on blood parameters.

BACKGROUND: Vitamin C and Carum copticum with antioxidant activity may eliminate the negative effects of heat stress on broiler performance and immunity.OBJECTIVES: This experiment was conducted to investigate the effect of feeding heat-stressed broilers with Carum copticum seed powder (CSP) and vitamin C (VC) on their growth performance, blood metabolites, carcass characteristics, and meat quality.METHODS: Herein, we carried out A 2*3 factorial arrangement in a completely randomized design with six treatments, including three levels of CSP (0, 0.75 and 1.5 % of diet), two levels of VC (0 and 250 mg/kg of DM of diet), and four replicates, on 240 one-day-old male Ross 308 broilers. The collected data were analyzed using PROC GLM of SAS. Treatment means were compared employing the Tukey test.RESULTS: The effect of CSP on their performance was not significant whereas VC treatment improved weight gain significantly (P<0.01). Interaction of CSP and VC on weight gain and feed conversion ratio was significant as broilers fed with 250 mg VC and those fed with 1.5 % CSP had the best WG and FCR (P<0.01). The addition of VC decreased the concentration of alkaline phosphatase in the blood (P<0.05). The heterophil to lymphocyte ratio was reduced through the use of VC and 1.5 % CSP (P<0.05). CSP supplementation at the rate of 1.5 % increased the relative weight of bursa of fabricius (P<0.05). Dripping loss percentage was reduced in birds fed with 1.5 % CP and VC (P<0.01). The effect of CSP and their interaction on water holding capacity was significant and the highest amount belonged to the birds fed with 1.5 % CSP (P<0.01). Additionally, VC increased meat ash percentage compared to the control group (P<0.01).CONCLUSIONS: The results of this study indicated that addition of 250 mg VC and 1.5 % CSP could be conducive to improving growth performance, blood metabolites, and meat quality of broilers under heat stress conditions.

BACKGROUND: Vitamin C is one of the important nutrients in fish culture and as a potent anti-oxidant, is of great importance in preserving cells against oxidation and boosting resistance in stress conditions and against pathogens. OBJECTIVES: The purpose of the present study is to add high level of vitamin C supplementation to rainbow trout (Oncorhynchus mykiss) diet reared at high density and analysis of growth indices, survival and carcass composition at two different stocking densities. METHODS: Rainbow trout juveniles with initial body weight of 9.6 ± 0.69 g at two densities of 50 and 100 pieces in 50 liters of water were fed two diets containing the same level of protein and fat. Experimental diets were diet 1 without adding vitamin and diet 2 with adding 1500 mg/kg of vitamin C. A total number of 900 rainbow trout juveniles in four treatments each with three replicates as T50 (0) (with the density of 50 and fed with diet 1), T100 (0) (with the density of 100 and fed with diet 1), T50 (C) (with the density of 50 and fed with diet 2) and T100 (C) (with the density of 100 and fed with diet 2) were randomly distributed in incubators. RESULTS: After 6 weeks of feeding, growth indices, feed conversion ratio and viability were significantly different between treatments (p<0.05). T50 (0) and T50(C) treatments had higher weight gain, specific growth rate and viability than T100 (0) and T100(C) (p<0.05). In the case of feed conversion ratio, it was higher in T100 (0) and T100(C) treatments compared to T50 (0) and T50(C) ones (p<0.05). Carcass composition was not significantly different between treatments (p>0.05). CONCLUSIONS: The results showed that vitamin C supplementation in the diet of rainbow trout juveniles did not have significant effects on growth indices, feed conversion ratio, survival and carcass composition but density was a key factor in growth, feed conversion ratio and survival in this species.