عنوان مقاله [English]
Introduction: Fungi can grow in feed that maintained under normal temperature and high moisture condition. At the same condition, the fungi can produce mycotoxins in the feed. In poultry production, mycotoxicosis caused by key mycotoxins such as: Aflatoxin B1, Ochratoxin, T2toxin, Zearalenone and deoxynivalenol (DON, vomitoxin). Mycotoxins especially aflatoxin had undesirable influence on feed intake, body weight, feed conversion ratio and carcass characteristics. The Aflatoxin infected feed cause injuries on poultry's carcass especially liver and heart. Various aspects of the aflatoxicosis in poultry husbandry including effects on bird’s performance, digestion, metabolism, and organ function, metabolism of the toxin, and remnant of toxic residues to poultry products have been the subjects of several comprehensive reviews. The aflatoxin has vast economic losses in poultry industry via increase the mortality and reduces the growth performance. In order to reducing aflatoxin side effects, some ways were proposed such as inactivation of toxin, toxin adsorbent. Bentonite is the main toxin adsorbent. Bentonite can decrease the aflatoxin absorption from gut. Therefore this study was done to evaluate the effects of different levels of physical modified Nanostructure bentonite (PNB) on growth performance, carcass components and blood indices in broilers challenged by aflatoxin B1 (AFB1).
Material and Methods: One hundred and sixty day-old Ross 308 broiler chicks were bought from a great hatchery in South Khorasan, Iran. The birds were assigned to 20 experimental units with the same mean group body weight at initial experiment. The birds were reared for 35 days. The experiment was conducted in a completely randomized design with 5 treatments, 4 replicates and 8 birds in each. Experimental groups consisted of: negative control (C), positive control (basal diet with aflatoxin B1) (AF) and three level 0.25, 0.50 and 0.75 % of Physical modified Nanostructure bentonite added to basal diet with aflatoxin B1(positive control). The aflatoxin were added to starter and grower diets at 500 ppm and to finisher diets at 1000 ppm. At 21 and 35 days of age, one bird from each replicate was randomly selected and bled and blood parameters involved the concentration of cholesterol, triglyceride, LDL, HDL, total protein, and enzyme activity of alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase were determined. One bird from each replicate of treatment were slaughtered and carcass components involved breast, thigh, abdominal fat, spleen, bursa of fabricius, and pancreas were weighed and the relative weight of organs were calculated. The data were analyzed by SAS software and general linear model (GLM) was used to analyze the data. The differences among means were determined by Tuckey's multiple range test.
Results and Discussion: The results showed that aflatoxin increased feed conversion ratio and reduced triglyceride as compared to control diet. The blood lipid was negatively influenced by infected aflatoxin diets in broilers. Supplementation of 0.25% Physical modified Nanostructure bentonite to the infected diet of broilers was significantly increased the feed intake, decreased the concentration of LDL (P<0.05). The lower relative weight of abdominal fat were observed in broilers fed diets contained aflatoxin and 0.25% Physical modified Nanostructure bentonite (PNB) (P<0.05). Birds fed infected diets and contained 0.75% PNB had higher triglyceride concentration compare to positive control. The ALT enzyme activity significantly increased in negative control treat compare to negative control and 0.50% PNB (P<0.05).In this research, the supplementation of Physical modified Nanostructure bentonite to broilers infected with aflatoxin reduced the undesirable effects of aflatoxin. As with previous research report that aflatoxin increased the feed conversion ratio and decreased the nutrient digestion and absorption. Inclusion of aflatoxin to broiler diets had undesirable effects on liver activity and liver injuries. The liver enzyme activities are indices to evaluate of liver function. The birds had higher liver enzyme activity, which may negatively affected by side effects of aflatoxin. The last literature were reported that the lower nutrient utilization might be a factor of the effects of the toxin on systemic metabolism rather than an effect on digestive functionality. Bentonite can adsorb the aflatoxin and reduce the side effects of them on broiler growth performance, digestive and liver function.
Conclusion: The result of this research showed that aflatoxin may decrease the performance parameters and addition of Physical modified Nanostructure bentonite reduced the negative effects of aflatoxin on performance and increased percentage of abdominal fat, therefore, the 0.5% Physical modified Nanostructure bentonite suggested to add in broiler diets contained aflatoxin.