The effects of feeding aflatoxin contaminated swine diets with clays on performance, mineral metabolism, immune response and liver function in weanling and growing Pigs

Abstract

Two studies were conducted using pigs to determine the effects of feeding aflatoxin contaminated diets (AC) with and without various clays on performance, liver function, mineral metabolism and humoral immune response. In the nursery phase of Study I, weanling pigs (n=96) were fed 1% sodium bentonite (SB) with and without AC (922 ppb). In the grower phase, 48 pigs from the nursery phase were continued on SB treatments for 5 wk; AC was discontinued. In the metabolism phase, 24 barrows from the nursery phase were continued on SB and AC. In the nursery phase, average daily gain (ADG), average daily feed intake (ADFI), and feed per gain (F:G) were depressed (P < .05), while serum gammaglutamyltransferase (GGT), alkaline phosphatase levels, and liver weights were increased (P < .05) in pigs fed AC. Feeding SB with AC increased (P < .05) ADG and ADFI, and lowered (P < .05) serum enzyme levels. In the grower phase, performance and serum chemistry did not differ across treatments, but livers of pigs previously fed AC remained larger (P <.01). Pigs fed AC had depressed (P < .05) Na absorption and increased P (P < .05) and Zn (P < .10) absorption compared with controls. SB decreased Na, K and Mg (P < .01), and P and Zn (P < .10) absorption when compared with pigs fed no SB. Pigs fed SB had lower Mg (P < .01) and Zn, Mn, and Na (P < .10) retention when compared to controls. SB decreased Ca absorption and retention when fed with AC and increased absorption when fed with control corn (P < .01). AC and SB treatments had no effect on Cu absorption or retention. Liver mineral levels were not affected in any of the phases. In Study II, two trials were conducted to examine the effectiveness of eight types of clays in reducing the negative effects of AC. [In trial I, seven types of clays (.5%) were fed with AC (500 ppb). ADG and ADFI, and urea N were reduced (P < .05), and serum aspartate aminotransferase and GGT were increased (P < .05) by feeding AC compared with NC. Feeding all the clays with the AC improved ADG and ADFI (P < .05) when compared with pigs fed the AC alone. Some clays were effective in recovering AC altered serum chemistry. In trial II, hydrated Na Al silicate or calcium bentonite (1%) were fed with AC (171 ppb). ADG and ADFI which were reduced for the first 4 wk by feeding AC (P < .05) were improved (P < .05). Humoral immune response was unaffected. In summary, feeding clay with AC can prevent some of the negative effects of aflatoxicosis with minimal influences on mineral metabolism.