The effect of infusion of urea into the vena cava on feed intake of finishing gilts

Effects of feeding high-protein corn distillers dried grains and a mycotoxin mitigation additive on growth performance, carcass characteristics, and pork fat quality of growing-finishing pigs

Two experiments investigated the effects of feeding diets containing 30% of novel high-protein distillers dried grains (HP-DDG) sources to growing–finishing pigs on growth performance, carcass characteristics, and pork fat quality. A four-phase feeding program was used in both experiments, and diets within phases were formulated based on National Research Council (NRC; 2012) recommendations for metabolizable energy and standardized ileal digestible amino acid content of HP-DDG. In Exp. 1, a total of 144 pigs (body weight [BW] = 20.3 ± 1.6 kg) were fed either corn-soybean meal control diets (CON) or 30% HP-DDG diets (HP-DDG) containing 0.7 mg/kg deoxynivalenol (DON), 0.1 mg/kg fumonisins (FUM), and 56 μg/kg zearalenone (ZEA) for 8 wk. On week 9, a mycotoxin mitigation additive (MA) was added to CON and HP-DDG diets, resulting in a 2 × 2 factorial arrangement of treatments consisting of: CON, CON + MA, HP-DDG, and HP-DDG + MA. Pigs fed HP-DDG had lower (P < 0.01) average daily gain (ADG) and average daily feed intake (ADFI) compared with those fed CON during the first 8 wk. After MA was added to diets, pigs fed HP-DDG diets without MA had lower (P < 0.05) overall ADG than those fed HP-DDG + MA and less (P < 0.05) final BW than pigs fed CON or CON + MA. Adding MA to HP-DDG diets containing relatively low concentrations of mycotoxins was effective in restoring growth performance comparable to feeding CON. In Exp. 2, a different source of HP-DDG was used, and mycotoxin MAs were added to all diets at the beginning of the trial. A total of 144 pigs (BW = 22.7 ± 2.3 kg) were fed either a corn-soybean meal control diet or a 30% HP-DDG diet containing 0.5 mg/kg DON and 0.8 mg/kg FUM for 16 wk. Pigs fed HP-DDG diets had less (P < 0.01) final BW and ADG than pigs fed CON, but there were no differences in ADFI. Feeding the HP-DDG diets reduced (P < 0.01) hot carcass weight, carcass yield, longissimus muscle area (LMA), and percentage of carcass fat-free lean compared with pigs fed CON but did not affect backfat (BF) depth. Pigs fed HP-DDG had less (P < 0.01) saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) content and greater (P < 0.01) polyunsaturated fatty acid (PUFA) and iodine value in BF than pigs fed CON. These results suggest that feeding diets containing relatively low concentrations of co-occurring mycotoxins can be detrimental to growth performance, and the addition of MA alleviated the growth reduction. Feeding 30% HP-DDG reduced BW, ADG, carcass yield, LMA, and percentage of fat-free lean of growing–finishing pigs but yielded acceptable pork fat quality.

Effects of dietary supplementation of l-methionine vs. dl-methionine on performance, plasma concentrations of free amino acids and other metabolites, and myogenesis gene expression in young growing pigs

Methionine (Met), the second or third limiting amino acid (AA) in typical swine diets, plays important roles in promoting swine health and growth, especially, muscle growth. Whereas dl-Met products have been used in swine industry for many years, l-Met products have been developed recently. This research was conducted to study the effects of supplemental l-Met or dl-Met on nutrient metabolism, muscle gene expression, and growth performance of pigs. Twenty crossbred young barrows (initial body weight [BW] 21.2 ± 2.7 kg) were randomly assigned to 20 individual pens and two dietary treatments according to a completely randomized design with pigs serving as the experiment unit (n = 10). Two corn and soybean meal-based diets (diets 1 and 2) were formulated to meet or exceed the recommended requirements for energy, AA, and other nutrients (NRC. 2012. Nutrient requirements of swine, 11th ed. Washington, DC: The National Academies Press; AMINODat 5.0). Crystalline l-Met and dl-Met were supplemented to diets 1 and 2 (both at 0.13%, as-fed basis), respectively. After 4 wk of an ad libitum feeding trial, BW and feed intake were measured to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (G:F). Blood samples were collected from the jugular vein for analyses of plasma AA and metabolite concentrations. The longissimus dorsi muscle samples were collected for analysis of myogenesis gene expression. Data were analyzed using Student's t-test. There were no differences (P = 0.56 to 0.94) in ADG, ADFI, or G:F between pigs fed the two experimental diets and no differences between diets were observed in plasma free AA concentrations. No differences were observed between pigs fed the two diets in expression of mRNA for eight myogenesis-related genes, which were myogenic differentiation 1, myogenin, myogenic factors 5, muscle regulatory factor 4 (a.k.a. myogenic factors 6), and myocyte enhancer factors 2A, 2B, 2C, and 2D. In conclusion, results of this experiment indicate that the bioefficacy of l-Met is not different from that of dl-Met, which is likely because of an efficient conversion of d-Met to l-Met by pigs.

Effects of dietary lysine levels on the concentrations of selected nutrient metabolites in blood plasma of late-stage finishing pigs

Lysine is the first-limiting amino acid (AA) in typical swine diets and plays very important roles in promoting growth performance of pigs. This research was conducted to study the effects of dietary lysine on blood plasma concentrations of protein, carbohydrate, and lipid metabolites of pigs. Eighteen crossbred finishing pigs (nine barrows and nine gilts; initial BW 92.3 ± 6.9 kg) were individually penned in an environment controlled barn. Pigs were assigned to three dietary treatments according to a randomized complete block design with gender as block and pig as experimental unit (6 pigs/treatment). Three corn and soybean meal-based diets were formulated to contain total lysine at 0.43%, 0.71%, and 0.98% (as-fed basis) for Diets I (lysine deficient), II (lysine adequate), and III (lysine excess) respectively. After 4 weeks on trial, jugular vein blood was collected and plasma was separated. The plasma concentrations of total protein, albumin, urea nitrogen (UN), triglyceride, total cholesterol, and glucose were determined using an ACE Clinical Chemistry System (Alfa Wassermann, Inc., West Caldwell, NJ, USA). Data were analysed using the GLM Procedure with PDIFF (adjust = T) option of SAS. No differences (p > 0.10) were found between barrows and gilts for any of the metabolites measured. While there were no differences (p > 0.10) between pigs fed Diets II and III in plasma concentrations of UN, albumin, and total cholesterol, the concentration of albumin in these pigs was higher (p < .05) than that of pigs fed Diet I, and the concentrations of UN and total cholesterol in these pigs were lower (p < .05) than that of pigs fed Diet I. There were no differences (p > 0.10) among the three dietary treatments in plasma concentrations of total protein, triglycerides, and glucose. These findings indicated that the plasma metabolite profile can be affected by changing dietary lysine content only. Thorough understanding how the plasma metabolite profile is alternated by dietary lysine will facilitate nutrient management for more sustainable swine production.