Impact of increasing dietary standardized ileal digestible arginine to lysine ratio from 0.85 to 1.15 and water-based arginine supplementation on growth performance and gut integrity of weaned pigs.

The objective of this experiment was to assess the influence of arginine (Arg) supplementation in water and/or feed on the growth performance and gastrointestinal health of newly weaned pigs. Two hundred and forty pigs (5.06 kg; PIC, Hendersonville, TN) were randomly allocated into 80 mixed-sex pens (3 pigs/pen) and subjected to a 2 × 4 factorial design. Two levels of Arg were supplemented in water (0% or 8% stock, dosed through a 1:128 proportioner) for the first phase (days 0 to 7), and four dietary arginine levels (0.85, 0.95, 1.05, and 1.15) standardized ileal digestible (SID) Arg to Lysine (Lys) ratios for the first two phases (days 0 to 7 and 7 to 21). All treatments were provided a common diet (0.96 SID Arg:Lys) for the last phase days 21 to 42. One pig per pen underwent a dual sugar absorption test of lactulose at 500 mg/kg and mannitol at 50 mg/kg of body weight (BW) via gastric tube on days 7 and 21 postweaning, with blood plasma collected 4 h later. The pig tested on day 7 was subsequently euthanized for intestinal tissue collection. Pen growth performance and feed disappearance were evaluated for 3 phases: days 0 to 7, 7 to 21, and 21 to 42 postweaning. The statistical analysis used linear models to examine the effects of SID Arg:Lys in the feed, Arg level in water, and their interactions, with pen as the experimental unit. Orthogonal contrasts were used to test the linear and quadratic effects of increasing SID Arg:Lys in the diet. Growth performance during the first period exhibited variability, reflected by negative gain-to-feed (G:F) ratios, caused by the enteric health challenge. Consequently, data were analyzed separately for each phase. Increasing dietary SID Arg:Lys caused a linear improvement (P = 0.04) in final BW (18.47 and 21.90 kg, for 0.85 and 1.15 SID Arg:Lys, respectively). A trend (P = 0.09) suggested a linear impact of dietary SID Arg:Lys on average daily gain during days 21 to 42. Arg supplementation, whether administered through water or diet, did not affect lactulose and mannitol absorption on both days 7 and 21, nor did it alter histological measurements in the collected ileum tissues on day 7 postweaning. In conclusion, increasing dietary SID Arg:Lys increased final BW but had no clear impacts on intestinal health within the parameters measured, potentially impacted by the rotavirus diagnosis in the first week post-wean.

Compensatory gain based on lysine level in finishing pigs after being fed lysine deficient 97% corn diets for 3 or 6 wk.

The objective of this experiment was to evaluate increasing the concentration of lysine on the compensatory gain of finishing pigs during their recovery period after being fed a 97% corn holding diet for 3 or 6 wk. One thousand six hundred and eighty pigs with a starting body weight of 73.5 ±â€…2.2 kg were blocked by starting body weight and assigned to a nested arrangement. Twenty replicates of seven treatments were comprised of two restriction lengths [3 weeks (3 wk) vs. 6 weeks (6 wk)], and three lysine concentrations during recovery (Lys:ME same as control:100; control + 10%: 110; control + 20%: 120) plus one control (CONT) that remained nutrient unrestricted. Pen weight and feed intake were recorded on days 0, 21, 41, and at marketing. Whole pens were marketed when the pen average met 130 kg and carcass measurements were collected. Data were analyzed by pen with the fixed effects of restriction length and lysine within restriction length. Nutrient restriction lowered (P < 0.01) average daily gain (ADG) compared to control, with 1.2, 0.4, and 0.5 kg for control, 3 wk, and 6 wk treatments, respectively. Restricted pigs showed decreased feed intake while restricted. After the respective restriction period, pigs were allowed a recovery diet until market. Previously restricted pigs had 16.7% and 27.3% greater (P < 0.01) ADG over control pigs for 3 and 6 wk treatments, respectively, in the first 3-wk of recovery. The lysine concentration in the recovery diet impacted (P < 0.01) the ADG with pigs allowed the highest lysine concentration having a 10% greater ADG than pigs fed the lower Lys:ME concentrations, for both restriction treatments. The increase in ADG was not paralleled by an increase in feed intake over control, thus, there was an improvement (P < 0.01) in gain to feed ratio in the recovery period. Control pigs reached market weight (131.5 kg) on experiment day 49 while pigs fed corn diets for 3 wk or 6 wk were slower to market (57 and 69 days, respectively; P < 0.01). Restricted pigs had greater backfat (CONT: 1.47, 3 wk: 1.55, 6 wk: 1.65 cm; P < 0.01), and decreased loin depth (CONT: 7.32, 3 wk: 7.03, 6 wk: 6.61 cm, P < 0.02) which was also impacted (P < 0.01) by lysine concentration. In conclusion, the use of restrictive diets reduced ADG and increased days to market. The use of recovery diets in which the Lys:ME ratio was greater than control pigs, resulted in increased compensatory growth.

Water- and feed-based arginine impacts on gut integrity in weanling pigs.

Two hundred and forty newly weaned pigs (PIC, Hendersonville, TN) were used to determine if supplementing additional arginine (Arg) either in the water or in the feed, and the combinations thereof, improved intestinal integrity and growth performance in nursery pigs. Each of the 80 pens contained three pigs (21 ± 2 d of age) which were randomly allotted to treatments in 4 × 3 factorial arrangement consisting of four water treatments (0%, 4%, 8%, and 12% Arg stock delivered through a 1:128 medication delivery system) in combination with three dietary Arg treatments (1.35%, 1.55%, and 1.75% standardized ileal digestible Arg; SID). Pigs and feeders were weighed at the d0, d6 (water and diet change), d20 (diet change), and d41 for the calculation of average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency (G:F). Eighty pigs, 1 pig/pen, were euthanized at d6 for ileum evaluation of villus height and crypt depth. The remaining pigs were taken off the Arg-water treatment and fed phase-2 diets formulated to contain 1.35%, 1.55%, and 1.75% SID Arg. All pigs received a common diet from d20 to d41. Data were analyzed by pen as repeated measures (SAS 9.4). No interaction between water- and dietary-Arg was detected on nursery pig growth performance. There was a significant quadratic effect of SID Arg in the feed on pig final body weight (BW), ADG, ADFI, and G:F (P ≤ 0.037), where feeding 1.55% dietary Arg tended to improve growth performance compared to the 1.35% level for the 41 d of the trial (P ≤ 0.088). The use of the stock 8% Arg in the water resulted in a reduction in crypt depth (0:132.5, 4:140.7, 8:117.3, 12:132.0; P ≤ 0.01) and an improvement in intestinal permeability. The 4% oral Arg significantly reduced villous height:crypt depth ratio (0:2.50, 4:2.09, 8:2.56, 12:2.43; P ≤ 0.02). In conclusion, the feeding of 1.55% Arg resulted in an improvement in nursery pig ADG, ADFI, G:F, and final BW but did not alter intestinal villi morphology; however, the use of Arg in the water resulted in an improvement in intestinal villi, but no phenotypical change in piglet growth in the nursery.

The impact of floor space allowance and dietary energy level on finishing pigs, from 65 to 120 kg, on growth performance.

The objective of this experiment was to evaluate the impact of lowering floor space allowance in finishing hogs from 65 to 120 kg when fed high- vs. low-energy diets on growth performance. Eighty-eight mixed-sex pens with 24 ±â€…1 pigs per pen were randomly assigned by weight in a complete block design to one of eight treatments in a 2 × 4 factorial arrangement with two energy levels: low (LE, 3267 ±â€…15 kcal/kg) vs. high (HE, 3389 ±â€…15 kcal/kg) accomplished through fat inclusion; and four floor space allowances: 0.6, 0.63, 0.65, and 0.67 m2/pig. Assigned floor space was accomplished by moveable gates in the rear of the pen which were adjusted at each pig removal until the marketing phase. Pen weight was measured at days 0, 29, and 48, with feed disappearance measured at days 29 and 48 to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (GF). Data were analyzed by pen (SAS 9.4, Cary, NC), as repeated measures, with the fixed effects of floor space allowance, dietary energy level, and the interaction between floor space allowance and energy level. For the overall experiment, decreased floor space had no effect (P > 0.1) on ADG, ADFI, or GF. Energy had a significant effect (P < 0.01) on ADFI (3.17 vs. 3.12 kg for LE and HE, respectively) and GF (0.35 and 0.36 for LE and HE, respectively), and tended to impact (P = 0.08) ADG (1.12 vs. 1.13 kg, for LE and HE, respectively). In conclusion, reducing space allowance from 0.67 m2 down to 0.6 m2 did not affect the growth performance of pigs from 65 to 120 kg. Pigs fed LE consumed more than the HE diets but had generally similar growth and no difference in body weight.