EFFECT OF SUPPLEMENTING GRADED LEVELS OF SELENIUM ON BROILER PERFORMANCE

Abstract

Seventy five, one day old Ross Hybrid broiler chicks from Coral Co. were randomly divided into five groups of 15 birds each. Control A, B receiving 0.1 mg/Kg Se, C, 0.2 mg/Kg Se, D, 0.3 mg/Kg Se and E, 0.4 mg/Kg Se. Each group was subdivided into 3 replicates of 5 birds each. Five isocaloric and isoenergetic feeds plus Se as sodium selenite were used to study the effect of Se on broiler chick performance. Birds received the same management in an experimental period of 49 days from 27th November 2002 to15th January 2003 at the Animal Production Research Centre (A.P.R.C) Hillat Ku Ku in cooperation and collaboration with the college of Veterinary Medicine and Animal Production, Sudan University of Science and Technology. Open housing system was used in a house of 8x4x3.5 meters. Lighting programme was 24 hrs and feeding and watering was adlib throughout the experimental period. Feed chemical analysis was made the APRC Nutrition Laboratory and the proximate analysis at the Veterinary Research Laboratory, Biochemistry, Nutrition and Toxicology Department at SOBA. Birds were slaughtered after4 hrs fasting and 2 birds were selected from each replicate to give 6 birds from each treatment and 30 birds from the whole flock. Birds were slaughtered manually and 2 heparinized blood samples were collected and preserved for further estimation of Hb, P.C.V. and total plasma protein levels. Samples from skeletal muscles, cardiac muscles and liver were taken for histological examinations. The experimental design was complete randomized design and statistical analysis method used was SPSS, (ANOVA) one-way analysis and LSD test were applied. Results showed no significant difference in weekly feed intake among all Se levels supplied but, 0.2 mg/Kg level in the second week was significantly higher than the control in this parameter. Body weight gain at 0.2 mg/Kg Se level attained the highest weight gained in all weeks except week 6.For feed 5 conversion ratio (F.C.R.) 0.2 mg/kg Se level had the least F.C.R. for the first 4 weeks and then no difference from the other treatments was observed. 0.2 mg/Kg Se level had the highest pre-slaughtering weight for all levels and was significantly higher than the control and 0.3 Se levels at (p<0.05). 0.2 mg/ Kg Se attained the highest final dressed carcass weight and was significantly higher than the control at (p<0.05). Legs weight did not show significant difference or pattern among all Se treatments. Head weight increased with Se level and 0.4 mg/kg Se level recorded a significantly higher weight than the control at (p<0.05). The liver weight was highest at 0.2 mg/Kg Se level and was significantly different than 0.0 and 0.3 mg/Kg Se levels(p<0.05). Both the gizzard and heart weights did not show any significant difference among all treatments but 0.1 mg/Kg Se level gave the highest weight for both organs indicating high sensitivity to Se. Mortality was generally low and not significant at different the Se levels indicating that up to 0.4 mg/Kg Se supplementation level was not lethal to broilers. Haematological parameter results showed no significance in Hb (g/dl) among all treatments and no special trend. P.C.V. (%) was highest at 0.2 mg/Kg Se level and was statistically significant (p<0.05) than the control and 0.3 levels. For plasma proteins (g/100ml) 0.4 mg/Kg Se level had the highest level and was significantly different than the control (p<0.05). The histological examination indicated that all Se levels had some effect on both skeletal and cardiac muscles starting from mild to severe degeneration, which increased with Se, level in the diet. Graded levels of Se indicated a clear effect on the liver tissue showing graded levels of congestion, haemorrhage, hepatic cell necrosis and fibrous tissue.