1. The effects of dietary aflatoxin (AF, 0.5, 1.0 and 2.0 mg/kg), ochratoxin (OA, 1.0, 2.0 and 4.0 mg/kg) or combinations of these on body weight gain, feed efficiency, organ weights and immune response were studied in broilers. 2. Significant growth depression, reduced food consumption and poor food conversion efficiency were recorded in broilers fed a diet containing the greater concentrations of AF (1 and 2 mg/kg) and OA (2 and 4 mg/kg). 3. The combination of 2 mg/kg AF and 4 mg/kg OA exerted the maximum adverse effect on growth, feed intake and feed efficiency, indicating a synergistic effect on performance. 4. AF at 2 mg/kg in the diet caused a significant increase in the relative weight of liver, whereas the relative weight of kidney was significantly increased at 4 mg/kg of OA. A significant decrease in the relative weight of the bursa of Fabricius was noted at the highest concentration of AF (2 mg/kg) and combinations of 1 and 2 mg/kg AF and 2 and 4 mg/kg OA. 5. Cell mediated immunity (CMI), in terms of mean skin thickness (MST) sensitive to dinitrochlorobenzene (DNCB), was significantly reduced in chicks given the combination of 2 mg/kg AF and 4 mg/kg OA. Haemagglutination (HA) titre against sheep red blood cells (SRBCs) peaked at 42 d of age. At 42 and 47 d of age, a significant decrease in HA titres was recorded in chicks given 4 mg/kg OA or a combination of AF (1 or 2 mg/kg) and OA (2 or 4 mg/kg). 6. AF at a dietary concentration of 1 mg/kg or more and OA at 2 mg/kg or more, either alone or in combination, caused severe reductions in growth and immune response.

1. A study was conducted with broilers to find out the effect of addition of methionine (0.0, 1.5, 3.0 and 4.5 g/kg) and choline (0.0, 1000 and 2000 mg/kg) to a basal diet containing crude protein, 221 g/kg, ME, 12.25 MJ/kg, methionine, 3.6 g/kg and choline, 1300 mg/kg. 2. Supplemental levels of methionine and choline were found to be ineffective in improving the growth, food consumption and food conversion efficiency of broilers. 3. However, a higher value for leucocyte migration inhibition was observed in chicks fed on the diet containing 6.5 g/kg methionine and 1300 mg/kg choline, indicating a significantly improved cellular immune response. 4. HI test and ELISA indicated enhanced antibody titres in chicks receiving 3.0 g/kg methionine and 3300 mg/kg choline, showing a significantly better humoral immune response. 5. Methionine and choline should be supplemented at levels higher than the recommended level of BIS for better health and production in chicks.

1. The effect of dietary vitamin E, selenium (Se) and their different combinations on body weight gain, food consumption, food conversion efficiency, leukocyte migration inhibition and antibody production was determined in broilers. 2. Chicks were fed on maize-soya bean based diets with concentrations of supplemental vitamin E varying from 0 to 300 IU/kg and selenium concentrations varying from 0 to 1 mg/kg either alone or in combination from 1 to 42 d of age. 3. The chicks were immunised for Newcastle Disease Virus (NDV) vaccine at 21 d. Per cent leukocyte migration inhibition (LMI) was studied on 42 d. Antibodies to NDV in serum were determined at 10 and 21 d post immunisation (PI). 4. Chicks receiving Se, 1 mg/kg and vitamin E 300 IU/kg had significantly higher cellular immune responses in terms of per cent LMI. 5. Maximum body weight gain and best efficiency of food utilisation were obtained in chicks fed diets containing 0.50 mg/kg Se and 300 IU/kg vitamin E. 6. Significantly higher antibody titres (HI and ELISA) at 10 d PI were attributed to 0.06 mg/kg and 150 IU/kg Se and vitamin E, respectively. 7. These data suggest that optimum growth and immune response may be achieved at supplemental level of Se of 0.06 mg/kg and vitamin E at 150 IU/kg. The vitamin E level is higher than that recommended by NRC (1984, 1994).

Studies were conducted to evaluate protein and energy utilisation in broilers fed diets containing various levels of aflatoxin (AF; 0, 0.5, 1 and 2 mg kg À1 ) and ochratoxin A (OA; 0, 1, 2 and 4 mg kg À1 ) either singly or in different combinations. Total protein efficiency (TPE) was reduced by 50.97, 76.52 and 132.75% at 2 mg kg À1 AF and 2 and 4 mg kg À1 OA respectively. Co-toxicity at two levels, 1 mg kg À1 AF þ 2 mg kg À1 OA and 2 mg kg À1 AF þ 4 mg kg À1 OA, resulted in significant reductions of 78.58 and 127.43% respectively in TPE. AF at all three levels and OA at 2 and 4 mg kg À1 caused significant decreases in net protein utilisation (NPU). Co-toxicity at all three levels led to significantly lower NPU. The reduction in NPU ranged from 18.68% at 0.5 mg kg À1 AF to 75.12% at 2 mg kg À1 AF þ 4 mg kg À1 OA. Significant reductions in metabolisable energy (ME) content were recorded at 1 and 2 mg kg À1 AF and all three levels of OA. ME content was reduced drastically when both toxins were fed simultaneously. It is suggested that both AF and OA adversely affect energy and protein utilisation in broilers, and this effect is exacerbated when both toxins are fed simultaneously. INTRODUCTIONNet protein utilisation (NPU) was found to be significantly lower and urinary nitrogen excretion significantly higher in ducklings fed a diet containing 30 mgkg À1 aflatoxin (AF) in comparison with those fed a toxin-free diet. 1 There was also a decrease in metabolisable energy (ME) content. 1 Graded levels of AF (1, 2 and 3 mg kg À1 ) significantly reduced the protein efficiency ratio and nitrogen absorbability in broilers. 2 It was also reported that ME was poorly utilised with 2 and 3 mg kg À1 dietary AF. 2 Dietary AF at a level of 1 mg kg À1 did not affect the digestibility of protein but caused a reduction in nitrogen utilisation from 31 to 43% and lowered the plasma concentration of methionine and cystine. 3 Ochratoxin A (OA) also caused malabsorption of nutrients. 4 Feeding of maize artificially contaminated with Penicillium spp and Aspergillus ochraceus to chicks resulted in reductions in dry matter and amino acid digestibility and energy utilisation. 5 AF at a rate of 1-2 mg kg À1 feed did not affect feed intake, protein digestibility or the absorption of amino acids, but reduced the utilisation of proteins. 6 Cereals can be contaminated by AFB 1 and OA and their metabolites before or during harvest or gradually during storage and processing. 7 The toxicity of individual mycotoxins can be enhanced or decreased when they occur as co-contaminants of feed,

The effect of dietary aflatoxin B 1 (AF) at levels of 0.5, 1 and 2 mg kg −1 , ochratoxin A (OA) at levels of 1, 2 and 4 mg kg −1 and their corresponding combinations on protein and energy utilisation as well as energy partitioning was studied in white leghorn laying hens. Protein retention was adversely affected at all levels of AF and OA either singly or in combination, though the effect was more evident with OA and AF + OA. Minimum protein retention was recorded in hens fed the combination of toxins at their highest levels (2 mg kg −1 AF + 4 mg kg −1 OA). Aflatoxin at 1 and 2 mg kg −1 and OA and AF + OA at all levels caused a significant reduction in metabolisable energy (ME) value of the diets. The minimum ME value was recorded for the diet containing both toxins at their highest levels (2 mg kg −1 AF + 4 mg kg −1 OA). A significant depression in egg energy deposition was observed with dietary inclusion of 1 and 2 mg kg −1 AF, 2 and 4 mg kg −1 OA and all levels of AF + OA in period I. In period II the reduction in egg energy deposition was significant at all levels of toxins either singly or in combination. Body energy deposition was adversely affected in hens fed the highest levels of AF (2 mg kg −1 ) and OA (4 mg kg −1 ) and all levels of AF + OA in period I. However, in period II a significant decrease in body energy deposition was observed at all levels of toxins except 1 mg kg −1 OA. A significant increase in maintenance energy (ME m /W 0.75 day −1 ) requirement was recorded in hens fed 2 mg kg −1 AF, 4 mg kg −1 OA and all levels of AF + OA. It is suggested that AF and OA either singly or in combination affect not only protein and energy utilisation in laying hens but also energy partitioning i.e. egg and body energy deposition and maintenance energy requirement. However, the combination of toxins (AF +OA) has more severe adverse effects on all parameters than the individual toxins because of their synergistic toxicity effect.

The present study was conducted to evaluate the effect of feed-grade enzyme supplementation in diets with varying levels of energy on the performance of growing and laying Japanese quails. Day-old Japanese quails, 504 in number, were subjected to six dietary treatments with six replicates at each treatment. Each replicate had 14 chicks. The dietary treatments consisted of three energy levels ie 12.15 MJ (2900 kcal), 11.30 MJ (2700 kcal) and 10.48 MJ (2500 kcal) ME kg −1 diet and two enzyme levels (0 and 0.5 g kg −1 diet). A metabolism trial was conducted at the fourth week of age. At the end of week 5, 10 quails (five of each sex) per treatment were sacrificed for carcass characteristics and 20 female quails from each of the six dietary groups were housed in individual laying cages and fed respective layer diet to study the laying performance and egg quality up to 20 weeks of age. Body weight gains of quails fed 12.15 MJ or 11.30 MJ ME kg −1 diets were significantly higher (p < 0.01) than those fed diets with 10.46 MJ ME kg −1 diet. Feed intake was significantly lower (p < 0.01) in birds that received diet with 12.15 MJ ME kg −1 than in birds that diets containing either 11.30 or 10.46 MJ ME kg −1 diet. Feed conversion ratio (p < 0.01) was best at 12.15, followed by 11.30 and 10.46 MJ ME kg −1 diet. Enzyme supplementation did not improve the growth performance, feed intake or feed conversion efficiency of quails. Enzyme addition also did not influence nitrogen retention or energy or dry matter metabolizability. The carcass characteristics did not differ because of energy or enzyme supplementation. Feed intake increased significantly (p < 0.01) as the dietary energy level decreased. The egg production and quality characteristics remained almost similar in all the dietary treatments. It was concluded that the optimum dietary energy level for quail was 12.15 MJ (2900 kcal) ME kg −1 during the growing phase and 11.30 MJ (2700 kcal) ME kg −1 during the laying phase. Addition of feed enzymes to conventional diets containing varying levels of maize, soyabean meal, fish meal and deoiled rice bran was not beneficial to improve growth, carcass traits, egg production performance or nutrient utilization.

The present experiment was conducted to assess the efficacy of methionine hydroxy analogue free fatty acid (MHA-FA) in comparison to DL-methionine (DL-Met) utilizing day-old commercial broiler chicks (n=300). The chicks were randomly distributed into 30 groups of 10 chicks each. Three dietary treatments, viz. D1-maize-soybean meal based basal diet (Control), D2control diet supplemented with DL-methionine to meet its requirements and D3-control

(1) Total and free gossypol contents were 6.2 and 0.8, 5.4 and 0.5, and 6.1 and 0.7 g/kg in meals processed (solvent extracted) from Bollgard (BG) II, non-BG II or commercial cottonseeds, respectively. (2) Broiler chicks were given one of 7 dietary treatments (iso-nitrogenous, 220 and 195 g crude protein/ kg diet at 0 to 21 and 21 to 42 d, respectively, at a metabolisable energy concentration of 12.15 MJ/kg). The treatments were: D1 (control, soybean meal [SBM] based), D2 and D3 (commercial CSM at 100 g/kg of diet with and without additional iron), D4 and D5 (BG II CSM with and without additional iron), and D6 and D7 (non-BG II parental CSM with or without additional iron). (3) Body weight gain, feed intake, feed conversion efficiency, nutrient utilisation, certain blood constituents and carcase traits were not significantly affected by dietary treatments. (4) Weights of bursa and thymus were significantly higher in groups given diets containing BG II or non-BG diets containing added iron. (5) The results suggest that low free gossypol content cottonseed meals, for example, BG II, non-BG II and commercial solvent-extracted CSM could be included at 100 g/kg in broiler diets, safely replacing soybean meal without additional iron.