Osteochondrosis prevalence and severity at 12 and 24 weeks of age in commercial pigs with and without organic-complexed trace mineral supplementation.

Maternal and progeny diets supplemented with 2 sources of trace mineral (TM) were evaluated for effects on the size and severity of osteochondrosis (OC) lesions in progeny produced by 64 Landrace × Large White sows. At breeding, sows were randomly assigned to maternal diets (gestation and lactation) consisting 1 of 2 TM treatments. One treatment consisted of inorganic TM (ITM) with ZnO, MnSO, and CuSO at concentrations to provide 150, 50, and 16.5 mg/kg diet of Zn, Mn, and Cu, respectively. The other treatment consisted of the same ITM concentrations plus an additional 50, 20, and 10 mg/kg diet of Zn, Mn, and Cu, respectively, supplied by a blend of AA-complexed TM (CTM) using Availa Sow. Within maternal dietary treatment groups, selected progeny ( = 280) were fed either ITM- or CTM-supplemented diets. The humerus and femur (1 each) from progeny euthanized at 12 ( = 80) or 24 wk ( = 200) were collected for microscopic (12 wk) or gross (24 wk) assessment of OC lesions. Microscopic OC lesions were present in all pigs at 12 wk. Dietary treatments had limited effects on OC prevalence or severity. A maternal × progeny diet interaction ( = 0.044) revealed femoral OC latens lesions that were approximately twice the size in progeny fed CTM that were produced by sows fed CTM compared with those found in pigs in the other 3 dietary treatment groups. At 24 wk, the sum of gross OC scores at predilection sites of the thoracic (elbow joint) and pelvic (stifle and hock joints) limbs remained similar among treatments, despite greater ( = 0.004) gross OC scores of the medial femoral condyle in progeny from sows fed CTM diets than in progeny from sows fed ITM diets, regardless of progeny diet. Progeny produced by sows fed CTM vs. ITM had increased ADG (0.71 vs. 0.68 ± 0.01 kg/d), regardless of the diet fed to progeny during the growth phases. Covariant analysis using ADG did not alter inferences about maternal or progeny diet effects on OC responses. Although 100% of progeny at 12 wk had histologically apparent OC lesions, only 3 of the 200 pigs examined at 24 wk had gross lesions of sufficient severity to potentially result in clinically apparent disease. Therefore, although some results imply that maternal and progeny CTM diets increased the size (12 wk) and severity (24 wk) of OC in 1 site (the femur), on the whole animal level, no evidence of lameness was noted.

Dietary organic zinc attenuates heat stress-induced changes in pig intestinal integrity and metabolism.

Dietary zinc (inorganic and organic or zinc AA complex forms) is essential for normal intestinal barrier function and regeneration of intestinal epithelium. Given that heat stress (HS) exposure can negatively affect intestinal integrity and caloric intake, possible nutritional mitigation strategies are needed to improve health, performance, and well-being. Therefore, our objective was to evaluate 2 dietary zinc sources and reduced caloric intake on intestinal integrity in growing pigs subjected to 12 h of HS. A total of 36 pigs were fed 1 of 2 diets: 1) a control diet (CON; 120 mg/kg of zinc from zinc sulfate) or 2) 60 mg/kg from zinc sulfate and 60 mg/kg from zinc AA complex (ZnAA). After 17 d, the CON pigs were then exposed to thermal neutral (TN) conditions with ad libitum intake (TN-CON), HS (37°C) with ad libitum intake (HS-CON), or pair-fed to HS intake under TN conditions (PFTN); the ZnAA pigs were exposed to only HS (HS-ZnAA). All pigs were sacrificed after 12 h of environmental exposure, and blood and tissue bioenergetics stress markers and ex vivo ileum and colon integrity were assessed. Compared with TN-CON, HS significantly ( < 0.05) increased rectal temperatures and respiration rates. Ileum villus and crypt morphology was reduced by both pair-feeding and HS. Both PFTN and HS-CON pigs also had reduced ileum integrity (dextran flux and transepithelial resistance) compared with the TN-CON pigs. However, ZnAA tended to mitigate the HS-induced changes in ileum integrity. Ileum mucin 2 protein abundance was increased due to HS and pair-feeding. Colonic integrity did not differ due to HS or PFTN treatments. Compared with the HS-CON, HS-ZnAA pigs tended to have reduced blood endotoxin concentrations. In conclusion, HS and reduced feed intake compromised intestinal integrity in pigs, and zinc AA complex source mitigates some of these negative effects.

Effect of feeding peroxidized dried distillers grains with solubles to sows and progeny on growth performance and metabolic oxidative status of nursery pigs.

This experiment evaluated the effects of including peroxidized corn dried distillers grains with solubles (DDGS) in diets for sows and nursery pigs on growth performance, vitamin E (VE), and Se status, and the incidence of mulberry heart disease (MHD) of nursery pigs. Sows (n = 12) were fed corn-soybean meal diets (C-SBM) or C-SBM diets with DDGS (40% and 20% in gestation and lactation, respectively) for 3 parities. In the third parity, 108 weaned pigs (BW = 6.6 ± 0.36 kg) were blocked by BW within litter, assigned to pens (2 pigs/pen; 5 and 4 pens per litter for groups 1 and 2, respectively), and pens were assigned 1 of 3 nursery diets: 1) corn-soybean meal (CON), 2) 30% peroxidized DDGS (Ox-D), and 3) 30% Ox-D with 5 × NRC (1998) level of VE (Ox-D+5VE) for 7 wk, in a 2 × 3 factorial arrangement of sow and nursery diets (n = 9 pens/treatment). The peroxidized DDGS source in nursery diets contained concentrations of thiobarbituric acid reactive substances (TBARS) and peroxide values that were 25 and 27 times greater than a reference corn sample. Sow colostrum, milk, and serum, as well as pig serum and liver samples, were analyzed for α-tocopherol and Se concentrations. Pig serum was analyzed for glutathione peroxidase activity (GPx), TBARS, and sulfur-containing AA (SAA). Pig hearts were evaluated for gross and histopathological lesions indicative of MHD, but none were detected. Pigs from sows fed DDGS tended to have reduced (P = 0.07) VE in serum during lactation and reduced VE at weaning (P < 0.01; 5.6 vs. 6.7 ± 0.1 µg/mL) compared with pigs from sows fed C-SBM. Inclusion of DDGS in sow diets reduced the VE status of pigs during lactation, but not in the nursery when MHD can be a concern. Pigs fed Ox-D+5VE (P = 0.08) tended to have, and those fed Ox-D (P = 0.04) had greater ADFI than pigs fed CON, but ADG was not affected (P > 0.1) by nursery diet. Feeding Ox-D or Ox-D+5VE increased (P < 0.05) serum α-tocopherol compared with CON (2.5, 2.8, and 3.4 ± 0.09 µg/mL, respectively), but TBARS and GPx were not affected by nursery diet. Serum concentration of SAA was 40% to 50% greater (P < 0.01) for pigs fed Ox-D or Ox-D+5VE compared with those fed C-SBM, which was likely due to greater (P < 0.01) SAA intake for pigs fed Ox-D. The antioxidant properties of SAA may have spared VE and Se and masked any effect of Ox-D on metabolic oxidation status. Therefore, increasing the dietary VE concentration was unnecessary in nursery diets containing Ox-D.

Effects of supplemental zinc amino acid complex on gut integrity in heat-stressed growing pigs.

Heat stress (HS) jeopardizes livestock health and productivity and both may in part be mediated by reduced intestinal integrity. Dietary zinc improves a variety of bowel diseases, which are characterized by increased intestinal permeability. Study objectives were to evaluate the effects of supplemental zinc amino acid complex (ZnAA) on intestinal integrity in heat-stressed growing pigs. Crossbred gilts (43±6 kg BW) were ad libitum fed one of three diets: (1) control (ZnC; 120 ppm Zn as ZnSO4; n=13), (2) control+100 ppm Zn as ZnAA (Zn220; containing a total of 220 ppm Zn; n=14), and (3) control+200 ppm Zn as ZnAA (Zn320; containing a total of 320 ppm Zn; n=16). After 25 days on their respective diets, all pigs were exposed to constant HS conditions (36°C, ∼50% humidity) for either 1 or 7 days. At the end of the environmental exposure, pigs were euthanized and blood and intestinal tissues were harvested immediately after sacrifice. As expected, HS increased rectal temperature (P⩽0.01; 40.23°C v. 38.93°C) and respiratory rate (P⩽0.01; 113 v. 36 bpm). Pigs receiving ZnAA tended to have increased rectal temperature (P=0.07; +0.27°C) compared with ZnC-fed pigs. HS markedly reduced feed intake (FI; P⩽0.01; 59%) and caused BW loss (2.10 kg), but neither variable was affected by dietary treatment. Fresh intestinal segments were assessed ex vivo for intestinal integrity. As HS progressed from days 1 to 7, both ileal and colonic transepithelial electrical resistance (TER) decreased (P⩽0.05; 34% and 22%, respectively). This was mirrored by an increase in ileal and colonic permeability to the macromolecule dextran (P⩽0.01; 13- and 56-fold, respectively), and increased colonic lipopolysaccharide permeability (P⩽0.05; threefold) with time. There was a quadratic response (P⩽0.05) to increasing ZnAA on ileal TER, as it was improved (P⩽0.05; 56%) in Zn220-fed pigs compared with ZnC. This study demonstrates that HS progressively compromises the intestinal barrier and supplementing ZnAA at the appropriate dose can improve aspects of small intestinal integrity during severe HS.