A. R. Alizadeh1 , M. Pakfar1, K. Karkoodi1, and H. Sadri2 Effects of Polyunsaturated Fatty Acids Supplementation on Performance and Immune Status of Young Holstein Calves A. R. Alizadeh1 , M. Pakfar1, K. Karkoodi1, and H. Sadri2 1 Department of Animal Science, Saveh Branch, Islamic Azad University, Saveh, Iran 2 Department of Clinical Science, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran Islamic Azad University University of Tabriz Background The milk fed calves are subject to high rates of sickness and motility. One approach is to optimize an animal’s natural immunity by nutritional means (Muturi et al., 2005). Polyunsaturated fatty acids (PUFA), particularly the n-3 and n-6 group, are dietary compounds with significant immunomodulatory potential (Hill et al., 2007). Calf starter contains low amount of n-3 FA. Previous studies confirm that adding fish oil to milk replacer altered various immune response and the effect was dose-dependent; however, either production performance nor indices of health were altered when fish oil replaced 5 to 10 % of the fatty acids in milk replacer (Ballou et al., 2008). There is limited information on the effects and requirements of specific PUFA for calf. Figure1. Comparison of blood cells from calves fed with oil sources on weaning day Objective Our objective was to study the effects of adding fish oil (FO; n-3) and soybean oil (SO; n-6) to milk replacer on performance and immune status of young calves. Results RBC, Hb and hematocrit were not affected by treatments during the course of the study. WBC (P< 0.01), lymphocyte (P > 0.05) and Neutrophill (P > 0.05) were affected by the FO (Figure1). Total protein, albumin, globulin and their ratio were not affected by the treatments. Similarly, blood cholesterol was unaltered by treatments. Daily weight gain increased in calves supplemented with FO compared with CTR (470, 430, and 310 g/d for FO, SO, and CTR, respectively; P < 0.05). Moreover, feed intake increased in FO group compared with others (940, 850, and 680 g/d for FO, SO, and CTR, respectively; P < 0.05). Materials and Methods Animal and Treatments Twenty one Holstein calves (n = 7 per treatment) were randomly assigned to three treatment groups in a private dairy farm (Mahsham Farm, Pakdasht, Iran). Calves were fed colostrum for the first 3 days, then calves were received 4 L/d milk replacer (Provi-milk super, Netherlands). Calves receiving no PUFA were used as controls (CTR). The study covered the period from 28 ± 2 d after birth through 14 d after weaning. The adaptation of calves to oil sources was started by 2-3 g/d and they could consume 35 g/d after nine days and until weaning. All treatments were supplemented with vitamin E (2.5 times the recommended dose). Measurements Fatty acid profile of fat sources was analyzed by gas chromatography (GC). FO contains 5.8 % EPA, 8.8 % DHA and C18:2 concentration of SO was 60 % in total fatty acids. The starter dry matter intake was recorded daily from 28 ± 2 until weaning (d 75). Calves were weighed at birth and at the commencement of the trail (28 ± 2 d) and on weaning day, before morning feeding. Blood samples were collected on d 2, d 25, weaning day, and 14 d after weaning. The red blood cells (RBC), hemoglobin (Hb), hematocrit, white blood cells (WBC), neutrophil (Neu), lymphocyte (Lym), serum proteins and cholesterol were measured. Data were analyzed using the MIXED procedure of SAS. Conclusion This study shows the beneficial effects of supplemental FO in milk replacers for young calves. Hill et al. (2009) measured that the 15:1 ratio of C18:2/C18:3 in calf starter exceeds the recommended optimum ratio of 10:1 for pig and 6:1 for preterm human infants. Improved some parameters clearly show necessity of revision of PUFA supplementation for young calves. Inclusion of FO in milk replacer improves feed intake and weight gain. The increase in WBC in calves supplemented with FO may instigate immune system response of young calf around weaning. In conclusion, FO could be recommended as a dietary supplement for milk fed calves. References - Ballou et al., 2008. Journal of Dairy Science. 91: 3488-3500. - Hill et al., 2007. The Professional Animal Scientist 23:135–143. - Hill et al., 2009. Journal of Dairy Science. 92: 670-676. - Muturi et al., 2005. Veterinary Parasitology. 129: 273-283. email: masouleh7@yahoo.com