Use of Yeast Cell Wall Extract for Growing Pigs Consuming Feed Contaminated with Mycotoxins below or above Regulatory Guidelines: A Meta-Analysis with Meta-Regression

Using a random-effects meta-analysis, the performance of growing pigs under a mycotoxin challenge (MT) with or without supplementation of yeast cell wall extract (YCWE, Mycosorb®, Alltech Inc.) was evaluated. Both MT and YCWE were also compared to animal controls not receiving mycotoxins (CTRL). Meta-regression was used to further explore the impacts of MT at/below (category 1) or above (category 2) global regulatory guidelines. Following the screening, 23 suitable references (30 mycotoxin treatments) were used. Overall, MT lowered average daily gain (ADG, p < 0.001) and average daily feed intake (ADFI, p < 0.0001) from CTRL by -84 and -165 g, respectively. Inclusion of YCWE during mycotoxin challenges (YCWE+MT, average 2.1 kg/ton) tended to result in greater ADG (+17 g, p = 0.068) compared to MT treatments. The gain-to-feed ratio (G:F) was not impacted by MT or YCWE+MT. Further investigation by meta-regression revealed that pigs fed MT in category 1 had lower ADG (-78.5 g, p < 0.001) versus CTRL, while YCWE+MT had higher ADG (+48 g, p < 0.001) over MT and was similar to CTRL. The ADFI was not impacted, although YCWE+MT had ADFI values similar to the CTRL. In category 2, ADG and ADFI of pigs fed MT were lower than CTRL (-85.1 and -166 g, respectively, p < 0.0001), with a tendency for YCWE+MT to result in higher ADFI (+25.3 g, p = 0.062). In summary, the inclusion of YCWE provided benefits to performance during common mycotoxin challenge levels (at or below regulatory guidelines).

Effect of long-term feeding of graded levels of deoxynivalenol on performance, nutrient utilization, and organ health of grower-finisher pigs (35 to 120 kg)

The objective of this study was to evaluate the effect of long-term feeding of graded levels of deoxynivalenol (DON) on performance, nutrient utilization, and organ health of grower-finisher pigs. A total of 240 mixed-sex grower-finisher pigs (35.9 ± 1.1 kg initial body weight, BW) were randomly assigned to 1 of 4 dietary treatments (6 pigs/pen; 10 pens/treatment) for 77 d. Diets consisted of a control diet without DON (CONT) and diets containing 1, 3, or 5 ppm DON (DON1, DON3, or DON5). Nitrogen-balance was determined in 1 pig/pen during weeks 6 and 12 of the study. Growth performance measures were taken weekly for average daily feed intake (ADFI), average daily gain (ADG), and gain:feed (GF) until day 77. Blood samples were collected on days 0, 14, 42, 56, and 84 from 1 pig/pen for analysis of indicators of liver and kidney function. On day 7, ADG and ADFI for pigs fed DON3 and DON5 diets were lower (P < 0.05) compared with DON1- and CONT-fed pigs. Overall, ADG and ADFI (days 0 to 77) were lower in DON3- and DON5-fed pigs compared with CONT and DON1 pigs (P < 0.05), with no difference in GF (P > 0.05). Final BW was reduced in DON3- and DON5-fed pigs (P < 0.05) compared with CONT and DON1, which were not different (P > 0.05). No significant (P > 0.05) treatment effects were observed on carcass characteristics. In the grower-phase, protein deposition (PD) was reduced in DON3 and DON5 pigs compared with CONT and DON1 pigs (P < 0.05). In the finisher phase, PD was not affected by dietary treatment (P > 0.05). There was no effect of dietary treatment on the majority of selected serum chemistry (P > 0.05). In summary, pigs exposed to diets containing > 1 ppm DON had reduced growth performance with little or no effect on nitrogen utilization, organ health, or carcass characteristics, suggesting that the negative effects of DON may be largely due to depressed feed intake.

Effect of long-term feeding of graded levels of deoxynivalenol (DON) on growth performance, nutrient utilization, and organ health in finishing pigs and DON content in biological samples

The prevalence of deoxynivalenol (DON) is a concern for swine producers, and although there has been extensive research into the effects of DON in pigs, focus has been in young pigs and/or in short-term studies. The objective of the study was to determine the effect of long-term exposure to DON-contaminated diets in finisher pigs. A total of 200 pigs (76.6 ± 3.9 kg initial weight) were group housed (five pigs per pen; n = 10 pens/treatment) in a 6-wk trial. Pigs were fed a wheat-barley-soybean meal-based control (CONT) diet with no DON or the basal diet in which clean wheat was replaced by DON-contaminated wheat and wheat screenings to provide DON content of 1, 3, or 5 ppm (DON1, DON3, and DON5, respectively). Individual BW and pen feed intake were recorded weekly to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F). Blood was collected on days 0, 14, and 43 and analyzed for indicators of liver and kidney health. Nitrogen (N)-balance was conducted immediately following the growth performance period to determine the effect of DON on nutrient utilization. Blood and urine samples collected during N balance were analyzed for DON content. Feeding DON reduced (P < 0.05) ADFI and ADG from days 0 to 28 compared with CONT, after which there was no effect of diet on ADFI and ADG. The G:F was lower (P < 0.05) in DON5 fed pigs compared with all treatments during days 0 to 7; however, no treatment effects on G:F was observed from days 8 to 42. Nitrogen retention was lower (P < 0.05) in DON3 and DON5 compared with DON1-fed pigs. Nitrogen retention efficiency was higher (P < 0.05) in DON1 compared with DON3 and DON5 and protein deposition for DON1 pigs was higher (P < 0.05) than all treatments. There were no treatment effects on indicators of liver and kidney health. As dietary DON intake increased, concentration of DON in blood and urine increased. Overall, although there was an initial decrease in ADG and ADFI in pigs receiving diets containing >1 ppm DON, pig performance recovered after a period of time, whereas nutrient utilization continued to be affected after recovery of performance. Moreover, the lack of DON on G:F indicates that the negative effects of DON on growth performance are largely due to reduced feed intake. Overall, although pigs maybe capable of adapting to intake of DON-contaminated diets, their final body weight will be reduced when fed diets containing >1 ppm DON.