Modelling the feed intake response of growing pigs to diets contaminated with mycotoxins

Effects of Three-Layer Encapsulated Tea Tree Oil on Growth Performance, Antioxidant Capacity, and Intestinal Microbiota of Weaned Pigs

Tea tree oil (TTO) exerts key roles in improving growth performance of pigs. However, knowledge is limited regarding comparative effects of Encp TTO and Un-encp TTO supplementation on growth performance of pigs. A study determined the effects of TTO or its capsulation on growth performance, antioxidant capacity, and intestinal microbiome of weaned pigs. A total of 144 healthy pigs (8.5 ± 0.24 kg) were subjected to four treatments for a 28-d trial with six replicates per treatment and six pigs per pen: negative control, NC; positive control, PC (antibiotic supplemented); Un-encp TTO (supplemented with unencapsulated TTO); Encp TTO (supplemented with encapsulated TTO). NC, TTO, and PC treatments were compared with regard to improved average daily gain (ADG), average daily feed intake (ADFI), feed conversion rate, nutrient digestibility, and intestinal morphology (p < 0.05) and decreased diarrhea rate. TTO- and PC-treated pigs had higher levels of serum superoxide dismutase, glutathione peroxidase, and immunoglobulin G; lower levels of liver aspartate aminotransferase and alanine aminotransferase; and improved concentrations of interleukin 10 (IL-10), tumor necrosis factor α, and IL-1β (p < 0.05). TTO- and PC-treated pigs had higher abundance of beneficial bacterial species Subdoligranulum and lower abundance of diarrhea associated species Escherichia-Shigella in cecal and colonic digesta (p < 0.05). Encapsulation of TTO preserved more activities of TTO than its unencapsulated counterpart by showing higher ADG, ADFI, and feed conversion rate during day 1 (d1) to d14 (p < 0.05) and tended to lower diarrhea rate (p = 0.083) and improve villous height/crypt depth (VH/CD) ratio (p = 0.089) in jejunum. Encapsulation of TTO also improved antioxidant indexes and decreased liver injury and inflammation accordingly (p < 0.05). Encapsulated TTO-treated pigs had higher abundance of beneficial Clostridium_sensu_stricto_1 and lower the abundance of harmful Escherichia-Shigella in cecal and colonic digesta (p < 0.05). Our results demonstrated TTO benefits on improving growth performance of weaned pigs and further proved that encapsulation of TTO was superior to its unencapsulated counterpart at multiples. Encapsulated TTO was similar to the PC group and could be potentially an alternative of feed antibiotics for weaned pigs.

Protective effect of a new generation of activated and purified bentonite in combination with yeast and phytogenic substances on mycotoxin challenge in pigs

The study aimed to investigate the efficacy of new mycotoxin adsorbents based on purified and activated bentonites combined with yeast and phytogenic compounds in fattening pigs. The experiment involved 96 pigs (31.2±2.4 kg). Control (C) group was fed a diet naturally contaminated with mycotoxins (5 mg/kg deoxynivalenol, DON) without an adsorbent. Treated groups received the feed with mycotoxin adsorbents: purified and activated bentonite (T1), purified and activated bentonite, yeast derivatives, phytogenic substances (T2), and purified, activated, and sulphurated bentonite with phytogenic substances (T3). Evaluated parameters involved growth performance, organ weight, small intestine and liver histopathology, complete blood count, serum biochemistry, antioxidant status of the organism and total and free DON content in urine. In all treated groups, an significant increase in intestinal GSH and GSH/GSSG ratio was observed when compared to C. No significant effects on liver and kidney weight, complete blood count, serum or intestinal malondialdehyde concentration, or total/free DON content in urine were observed. All adsorbents improved histopathological findings in the liver when compared to C. Moreover, T1, and T2 groups showed no presence of inflammatory reaction or necrotic changes in the livers. Although, mycotoxin adsorbents investigated in this study had no significant impact on pig growth performance, they reduced the oxidative stress, and on the tissue level they protected the jejunal tissue and liver parenchyma under deoxynivalenol challenge.

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.

A novel feeding behavior index integrating several components of the feeding behavior of finishing pigs

Describing the feeding behavior of pigs is difficult given the large day-to-day variations observed for a given animal. The objectives of this study were to create an index that integrates the information from several components of feeding behavior in order to account for intra-animal variation within a day and between days, and to evaluate the capability of this index to study the impact of relevant nutritional factors affecting feeding behavior. Feed intake information from 160 pigs during the last 28 d of the growing phase from three studies was used. For each pig, the sum of the absolute values of the deviation areas between the regression line of the relative cumulative feed intake and the observed cumulative feed intake was used to calculate the weekly index measuring the irregularity of feed intake (IIFI). Spearman's correlations of IIFI with the number of daily meals (r = -0.42; P < 0.001), meal duration (r = 0.38; P < 0.01), and feed intake per meal (r = 0.41; P < 0.01) indicate that pigs with high IIFI have fewer meals of longer duration and higher feed intake compared to pigs with low IIFI. This shows that IIFI captures information from several components of feeding behavior. Analysis of variance showed no effect of treatment on feeding behavior for datasets 1 and 2. However, the correlation between IIFI and dietary levels of CP (r = 0.34) indicates that diets high in CP were associated with pigs having more irregular meals. In dataset 3, pig feeding behavior was more regular in control diets than in pigs fed fibrous diets (IIFI; 164 vs. 197, respectively; P < 0.05). Additionally, IIFI was smaller in pigs fed canola by-product diets than in pigs fed wheat by-product diets, indicating that the source of fiber may also influence the feeding behavior of pigs. In most cases, IIFI was more effective at identifying differences in feeding behavior between dietary treatments than conventional feeding behavior variables. These results show the ability of IIFI to integrate information from several conventional components of the feeding behavior of pigs and its potential to successfully evaluate the effect of nutritional factors on feeding behavior.

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.