Effect of various levels of aflatoxin and ochratoxin A and combinations thereof on protein and energy utilisation in broilers

Abstract

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,

Aflatoxicosis: Lessons from Toxicity and Responses to Aflatoxin B1 in Poultry

“…Direct investigations of AFB1-effects on absorption or retention of individual nutrients have had variable results [34,194,196,[205][206][207][208]. Exposure to AFB1 decreases the apparent metabolizable energy poultry can obtain from their diet [34,195,196,[205][206][207].…”

“…Exposure to AFB1 decreases the apparent metabolizable energy poultry can obtain from their diet [34,195,196,[205][206][207]. Therefore, increased dietary nutrients are needed to compensate for impaired uptake.…”

Evaluation of Antimycotoxin Effects of Humate and Hydrated Sodium Calcium Aluminosilicate on Broilers Toxicated with Aflatoxin

“…The reduction in growth performance upon feeding aflatoxin might be attributed to reduced protein synthesis as citied by (Verma et al,2002) reduce appetite by (Sharlin et al,1980), increase lipid excreation in dropping (Osbrne and Hamilto,1981). Hassan et al (2000) reported that the toxicity of AFB1 as characterized by reduction in body weight gain as interfere with normal metabolic pathway through the inhibition of protein synthesis and enzymes system that is involved in carbohydrate metabolism and energy release.…”

Broyler Piliçlerde Rasyona Katılan Geyikotu Esansiyel Yağının Aflatoksin B1 Toksisitesinin Azaltılmasındaki Etkinliği

“…The reduced feed intake may be related to protein catabolism and an increase in the level of ammonia in blood. Moreover, the adverse effects of aflatoxin on growth performance have been related with a decrease in the protein and energy utilization [17] , probably as a consequence of a deterioration of the digestive and metabolic efficiency of the birds.…”