Effects of reduced crude protein diets while maintaining essential amino acid concentrations on growth performance, nitrogen output, ammonia production, and meat yield.

An experiment was conducted to determine the effect of feeding reduced crude protein (CP) diets to Ross × Ross 708 male broilers while providing adequate essential amino acid (AA) concentrations on growth performance, nitrogen (N) and ammonia output, and carcass characteristics from d 1 to 33 post hatch. Birds received 1 of 6 dietary treatments (10 replicate pens per treatment) varying in CP content. Diet 1 (control) was formulated with DL-Met, L-Lys, and L-Thr (23.2, 20.7, and 19.1% CP) in the starter (1-14 d of age), grower (15-25 d of age), and finisher (26-33 d of age) periods, respectively. Dietary L-Val, Gly (only in starter period), L-Ile, L-Arg, and L-Trp were sequentially supplemented in the order of limitation in Diets 2 through 6. Dietary CP was reduced gradually across the dietary treatments resulting in a CP reduction in Diets 1 to 6 by 3.4, 3.4, and 2.3% points in the starter, grower, and finisher periods, respectively. At d 14, 25, and 33 posthatch, feed conversion decreased (P < 0.05) with L-Val addition (Diet 2) and increased (P < 0.01) with L-Val to L-Trp addition (Diet 6) to the control. Dietary treatments did not alter weights and yields of carcass, breast, drum, or thighs. Dietary CP reduction with added L-Val (Diet 2), L-Val to L-Arg (Diet 5), or L-Val to L-Trp (Diet 6) increased abdominal fat (P < 0.01) compared with control. Nitrogen excretion (g/bird; P = 0.003) and equilibrium ammonia concentration (mg/kg; P = 0.041) at day 33 reduced by 16% and 48% respectively in birds fed reduced-CP diets with L-Val to L-Trp (Diet 6) compared with control-fed birds. This study indicated that sequential addition of supplemental AA in the order of limitation from DL-Met to L-Arg allowed reduction of dietary CP beyond 2%-point without depressing growth performance and meat yield of broilers from day 1 to 33 while reducing nitrogen excretion and ammonia emissions.

Effects of dietary protein level and age at photo stimulation on reproduction traits of broiler breeders and progeny performance.

A study with a 2 × 2 factorial arrangement was conducted to determine the effects of 2 dietary crude protein levels, high (CPh) or low (CPl), supplemented with free amino acids (AA), and 2 ages at photo stimulation (PS)-early (21 wk; PSe) or late (23 wk; PSl)-on reproduction traits of broiler breeders and progeny performance. Diets were isocaloric, and calculated CP content of the CPl diets was 15 g/kg lower than the CPh diets during all phases. A total of 480 female and 64 male Ross 308 breeders of 20 wk of age were used. Total egg production was similar between CPl and CPh birds during phase 1 and 2 but was reduced by 2.8 eggs for CPl birds during phase 3. For the overall laying period, CPl birds tended (P = 0.075) to produce 4.7 fewer total eggs. Hatchability of set eggs was similar between CPl and CPh birds during phases 1 and 2 but tended (P = 0.064) to be lower for CPl birds in phase 3. PSe birds showed an advanced age at sexual maturity and age at peak production of 4.6 and 5.3 d, respectively, resulting in 2.5 more total eggs during phase 1. During phase 1, PSe birds showed an almost 5% increased fertility. Chick production in phase 1 was higher for PSe birds resulting in a tendency (P = 0.071) to higher overall chick production of almost 8 chicks. Progeny from early PS breeders showed an overall significant lower feed conversion ratio (FCR). It was concluded that egg and chick production during phases 1 and 2 were not affected by dietary CP level, but egg and chick production was reduced for CPl birds during phase 3. On the other hand, PSe birds showed an increased number of chicks. It is possible to decrease CP level of breeder diets with comparable reproduction from 22 to 46 wk; however, this is questionable for phase 3. For maximal chick production, early PS is recommended.

Effect of salmon protein hydrolysate and spray-dried plasma protein on growth performance of weanling pigs.

Two experiments, each consisting of 2 trials, were conducted to determine the effect of salmon protein hydrolysate (SPH) and spray-dried plasma protein (SDPP) fed during the first week postweaning and their subsequent effect on the growth performance of weanling pigs. Pigs were fed in a 3-phase feeding program with durations of 7 d for phase 1 in both Exp. 1 and 2; 14 or 15 d for phase 2 in Exp. 1 and 2, respectively; and 7 or 8 d for phase 3 in Exp. 1 and 2, respectively. Dietary treatments were fed only during phase 1, whereas the same diet was fed to all pigs in phases 2 and 3. Pigs were blocked by initial BW and sex, and littermates were balanced across treatments. Data from the 2 trials within each experiment were combined and analyzed together; no treatment × trial interactions (P > 0.10) were observed. In Exp. 1, a total of 324 weanling pigs (10 replications of 5 or 6 pigs per pen) with an average initial BW of 6.4 ± 1.3 kg were assigned to 1) a control diet with no SPH or SDPP, 2) 1.5% SPH, 3) 3.0% SPH, 4) 1.5% SDPP, 5) 3.0% SDPP, or 6) 1.5% SPH + 1.5% SDPP. Experiment 2 was similar to Exp. 1, but red blood cells were removed from all diets to reduce diet complexity. In Exp. 2, weanling pigs (n = 320, 14 replications of 5 or 6 pigs per pen) with an average initial BW of 5.4 ± 1.2 kg were assigned to 1) a control diet with no SPH or SDPP, 2) 1.5% SPH, 3) 1.5% SDPP, or 4) 1.5% SPH + 1.5% SDPP. Three batches of SPH were used, and each batch was analyzed for AA composition. In Exp. 1, the inclusion of SDPP or SPH during phase 1 did not affect (P > 0.10) ADG, ADFI, or G:F compared with those of pigs fed the control diet. No carryover effects on growth performance were observed in any of the subsequent phases. Overall, G:F was greater (P = 0.08) in pigs fed the 1.5% diets compared with those fed the 3.0% diets. In Exp. 2, no differences (P > 0.10) were observed in ADG, ADFI, or G:F among pigs fed the SPH or SDPP diets compared with those of pigs fed the control diet. Pigs fed the combined diet had greater (P < 0.10) overall ADFI compared with that of pigs fed the control diet, but ADFI was similar to that of pigs fed the SPH and SDPP diets. These results indicate that inclusion of up to 3% SDPP or SPH in diets fed during the first week postweaning did not affect the growth performance of weanling pigs, and no subsequent carryover effects were observed. Salmon protein hydrolysate did not affect the growth performance of weanling pigs and may be considered an alternative protein source in diets for weanling pigs.

Effect of milk chocolate product on week-1 feed intake and growth performance of weanling pigs.

Experiments were conducted to assess the effect of dried whey (DW; 70% lactose) or milk chocolate product (MCP; 20% lactose and 60% sugars) on wk-1 feed intake and growth performance of pigs. Diets contained 1.60, 1.40, 1.40, and 1.20% total Lys for phase 1 (d 0 to 7), 2 (d 7 to 14), 3 (d 14 to 21), and 4 (d 21 to 35), respectively. Pigs were blocked by initial BW; sex and littermates were balanced across treatment; treatments were replicated with a minimum of 5 pens of 4 pigs each. Pigs were weaned at 24, 19, and 24 d of age with an initial BW of 6.5, 6.0, or 6.3 kg for Exp. 1 to 3, respectively. In Exp. 1 and 2, the treatments were 1) negative control (NC), no lactose added, 2) positive control (PC) with DW, 3) 25% replacement of the level of DW of the PC diet with MCP (25MCP), and 4) 50% replacement of the level of DW of the PC diet with MCP (50MCP). The level of DW or combinations of DW and MCP were 20, 10, and 5% for phases 1, 2, and 3 respectively. A common diet with no lactose was fed during phase 4. In Exp. 3, the treatments were 1) NC, 2) PC, and 3) 100% replacement of the level of DW of the PC diet with MCP (100MCP). In the combined data of Exp. 1 and 2, daily collected feed intake during wk 1 was increased (P < 0.10) from d 3 to 7 for the PC pigs; on d 2, 3, 4, and 7 for the 25MCP pigs; and from d 2 to 7 for the 50MCP pigs compared with the NC pigs. There was no difference (P > 0.10) on any day of wk 1 among pigs fed the PC and MCP diets. During phase 1, ADG and ADFI were increased (P < 0.10) for the PC, 25MCP, and 50MCP pigs compared with the NC pigs, but G:F was not affected (P > 0.10). During phases 2, 3, 4, and overall, there were no differences (P > 0.10) in growth performance among pigs fed the PC and MCP diets. In Exp. 3, collected daily feed intake during wk 1 was increased (P < 0.10) from d 2 to 5 for PC pigs and on d 1 and 2 for the 100MCP pigs compared with the NC pigs. However, there was no difference (P > 0.10) on any day of wk 1 between the PC and 100MCP pigs. Growth performance was not affected (P > 0.10) during any phase of the experiment. Combined data from Exp. 1, 2, and 3 using the NC and PC diets indicated that dietary DW increased (P < 0.10) final BW and increased ADG and ADFI during phases 1, 2, 3, and overall. These results indicate that partial or total replacement of DW with MCP had no effect on wk-1 feed intake or growth performance of weanling pigs and that MCP could be considered as a formulation alternative to DW.

Comparison of dried whey permeate and a carbohydrate product in diets for nursery pigs.

Three experiments were conducted to compare dried whey permeate (DWP; 80% lactose) and a carbohydrate product (CHO; 40% lactose, 30% sucrose, and 10% glucose) for nursery pigs. Pigs were fed in a 3-phase feeding program, and diets contained 1.6, 1.4, and 1.2% total Lys for phases 1 (d 0 to 7), 2 (d 7 to 21), and 3 (21 to 28). Dietary treatments included 1) control (no lactose), 2) low level of DWP, 3) high level of DWP, 4) low level of CHO, and 5) high level of CHO. In Exp. 1 (4 reps of 4 pigs per pen; initial BW = 7 kg and 23 d of age), the low and high levels used for each source in each phase were phase 1 (12.5 and 25%), phase 2 (10 and 20%), and phase 3 (6 and 12%). In Exp. 2 (6 reps of 5 pigs per pen; initial BW = 8 kg and 26 d of age) and 3 (4 reps of 4 pigs per pen; initial BW = 6 kg and 21 d of age), the inclusion levels were phase 1 (6 and 12%), phase 2 (3 and 6%), and phase 3 (common diet with no lactose). In Exp. 1, pigs fed diets with DWP or CHO had increased ADG (P = 0.02 and P = 0.01) and ADFI (P = 0.01) compared with pigs fed the control diet during phase 1. Gain:feed was reduced (P = 0.08) for pigs fed diets with CHO. During phases 2, 3, and overall, ADG, ADFI, and G:F were not affected (P > 0.10) by diet. In Exp. 2, pigs fed diets with CHO had increased ADG (P = 0.08 and P = 0.07) and ADFI (P = 0.04 and P = 0.01) compared with pigs fed the control diet during phases 1 and 2. Pigs fed diets with CHO had increased ADFI (P = 0.08 and P = 0.07) in phases 1 and 2 and increased ADG (P = 0.02) in phase 2 compared with pigs fed diets with DWP. Overall, pigs fed diets with DWP and CHO had increased ADFI (P = 0.06 and P = 0.01) compared with pigs fed the control diet, but ADG was increased (P = 0.07) for pigs fed diets with CHO. In Exp. 3, ADG, ADFI, and G:F were not affected (P > 0.10) by DWP or CHO during phase 1. Daily BW gain was increased (P = 0.02 and P = 0.07) for pigs fed diets with DWP or CHO during phase 2 compared with pigs fed the control diet. Overall, ADG was increased (P = 0.05) for pigs fed diets with DWP, but ADFI and G:F were not affected. Results from the combined data of Exp. 2 and 3, indicated that overall ADG (P = 0.05 and P = 0.04) and ADFI (P = 0.04) were increased in pigs fed diets with DWP or CHO compared with pigs fed the control diet. These data suggest that DWP or CHO improve growth performance of weanling pigs.