Insoluble fiber sources in mash or pellets diets for young broilers. 2. Effects on gastrointestinal tract development and nutrient digestibility1.

The effects of feed form and dietary fiber on the development of the gastrointestinal tract (GIT) and nutrient digestibility were studied in broilers at 8 and 21 d of age. The experiment included 14 treatments arranged as a 2 × 7 factorial with 2 feed forms (mash vs. pellet) and 7 diets that consisted in a low fiber diet and 6 extra diets resulting from the combination of 3 insoluble fiber sources [oat hulls (OH), rice hulls, and sunflower hulls] and 2 levels of inclusion (2.5 and 5.0%). Pelleting decreased the relative weight (% BW) of the full GIT, and empty gizzard (P < 0.001) and the relative length (cm/kg empty BW) of the small intestine and ceca (P < 0.001) and increased full crop (P < 0.001) and liver (P < 0.05) weights. Fiber inclusion increased the empty weight and the fresh digesta content of the gizzard (P < 0.001) but had limited and inconsistent effects on the weight of the full GIT or the length of the small intestine and ceca. Gizzard pH decreased with mash feeding and fiber inclusion (P < 0.001). Pelleting decreased ether extract retention (P < 0.05) but did not affect N retention or AMEn of the diets. Fiber inclusion improved nutrient retention (P < 0.05 to P < 0.001) with more pronounced effects with OH than with sunflower hulls or rice hulls inclusion. The AMEn of the diets increased (P < 0.05) with 2.5% of fiber inclusion but no extra benefits were obtained with a further increase to 5.0%. Starch ileal digestibility increased with mash feeding (P < 0.001) and fiber supplementation (P < 0.05). In summary, pelleting increases full crop weight and gizzard pH and decreased full gizzard weight and starch ileal digestibility. Moderate amounts of insoluble fiber, especially OH, increases gizzard weight, reduces gizzard pH, and improves nutrient digestibility in young broilers.

Inclusion of insoluble fiber sources in mash or pellet diets for young broilers. 1. Effects on growth performance and water intake.

The effects of feed form and the inclusion of insoluble fiber in the diet on growth performance and water intake were studied in female broilers from 0 to 21 d of age. The experimental design was completely randomized with 14 treatments arranged as a 2 × 7 factorial with 2 feed forms (mash vs. pelleted) and 7 diets that consisted of a control diet low in fiber (1.6% crude fiber) based on broken rice, fermented soybean meal, and fish meal and 6 extra diets that resulted from the inclusion of 3 insoluble fiber sources (oat hulls; OH, rice hulls; RH, and sunflower hulls; SFH) at 2 levels (2.5 vs. 5%). Each treatment was replicated 6 times. Broilers fed pellets had 32% greater ADG and 3% better feed to gain ratio (F:G) than those fed mash (P ≤ 0.001). The inclusion of the fiber sources improved ADG (P ≤ 0.05) and F:G (P ≤ 0.05). Pelleting increased (P ≤ 0.001) water intake from 6 to 8 d, water-to-feed intake ratio from 18 to 20 d, and moisture content of the excreta at 20 d of age. The inclusion of the insoluble fiber sources increased water intake (P ≤ 0.05) from d 18 to 20 but not from d 6 to 8. Increasing the level of fiber inclusion from 2.5 to 5.0% tended to increase (P = 0.086) moisture content in the excreta at d 20. Pelleting and the inclusion of insoluble fiber sources improved ADG and F:G in broilers fed low-fiber diets, and the improvements observed were more pronounced with pellets than with mash. Growth performance of young broilers improves with the addition of moderate amounts of structural insoluble fiber in the diet, regardless of feed form. The inclusion of OH or SFH into low fiber diets was more beneficial for improving broiler performance than the inclusion of RH.

Ileal digestibility of amino acids of unheated and autoclaved pea protein concentrate in broilers.

The effects of autoclaving 2 varieties of micronized (fine grinding) pea protein concentrate (PPC) on the ileal digestibility (ID) of CP and amino acids (AA) were studied in broilers. There was a control diet based on fermented soybean meal (FSBM) and 4 extra diets in which the FSBM was substituted on a CP basis by PPC from 2 different pea cultivars (PPC-1 and PPC-2), either unheated or autoclaved. Chicks were fed a common diet from 1 to 17 d of age and, then, their respective experimental diets from 18 to 21 d of age. Each treatment was replicated 6 times. Autoclaving reduced trypsin inhibitor activity (TIA) but had little effect on the saponin content of the PPC. The apparent ID (AID) of CP was similar for the FSBM and the unheated PPC and lower for both than for the autoclaved PPC. Autoclaving improved (P < 0.001) the AID of CP (87.6 vs. 82.2%) and most indispensable AA (e.g., 92.1 vs. 88.8% for Lys and 83.6 vs. 76.5% for Thr) of the PPC. The improvement in CP and AA digestibility with autoclaving varied with the PPC used and was consistent with the reduction in TIA observed (9.4 to 2.8 mg/g for PPC-1 vs. 9.1 to 5.3 mg/g for PPC-2). The standardized ID (SID) of most indispensable AA was similar for the FSBM and the PPC-2 and higher for both than for the PPC-1 (P < 0.05). For Lys, the lowest SID value was observed for the FSBM and the highest for the PPC-2 either unheated or autoclaved. It is concluded that the ID of the AA of the PPC improved with heating and was in general higher for the autoclaved PPC than for the FSBM. Consequently, heat processed PPC is a good alternative to FSBM and unheated PPC in starter diets for broilers.

Influence of source of soybean meal and lysine content of the diet on performance and total tract apparent retention of nutrients in broilers from 1 to 36 days of age.

The influence of soybean meal (SBM) source and total Lys content of the diet on performance and total tract apparent retention of nutrients was evaluated in broilers from 1 to 36 d of age. There were 6 treatments arranged factorially with 2 sources of SBM [regular SBM with 46.3% CP (R-SBM) and high-protein SBM with 48.6% CP (HP-SBM)] and 3 Lys:AME(n) ratios (Lys:ME; 380, 415, and 450 mg of total Lys:1,000 kcal of AME(n) from 1 to 21 d; and 312, 338, and 364 mg of total Lys:1,000 kcal of AME(n) from 22 to 36 d of age). From 1 to 36 d of age, broilers fed the HP-SBM diets had higher ADG and better feed:gain ratio (F:G) than broilers fed the R-SBM diets (P < or = 0.001). Both ADG and F:G improved (P < or = 0.05) with increases in the Lys:ME ratio. From 1 to 21 d of age, ADG and F:G (P < or = 0.001) were improved when the Lys:ME ratio increased and the benefits were more pronounced with the diets based on R-SBM. From 22 to 36 d of age, increasing the Lys:ME ratio from 312 to 338 increased ADG (P < or = 0.05) and F:G (P < or = 0.01), but no further improvements were observed when the ratio was increased to 364. The total tract apparent retention of DM and gross energy of the diets were higher (P < or = 0.05) for the HP-SBM than for the R-SBM diets. An increase in the Lys:ME ratio reduced organic matter and N retention (P < or = 0.05). The improvements in growth performance and nutrient retention observed in broilers fed the HP-SBM diets with respect to those fed the R-SBM are consistent with a better availability of nutrients of the high-protein meal. In addition, the results indicate that Lys requirements of broilers are at least, 30, 20, and 8% higher from 1 to 10, 10 to 21, and 21 to 36 d of age, respectively, than current NRC recommendations.

Apparent ileal digestibility of energy, nitrogen, and amino acids of soybean meals of different origin in broilers.

The coefficient of apparent ileal digestibility (CAID) of DM, gross energy (GE), N, and amino acids (AA) of 6 soybean meal (SBM) samples were compared in 21-d-old broilers. In addition, the digestibility of DM and N of diets that contained these SBM were tested in vitro. Four of the SBM were of South American origin, had a CP content varying from 45.2 to 47.2% and a trypsin inhibitor activity (TIA) varying from 4.1 to 6.5 mg/g, and were collected from local traders. The other 2 SBM were from US origin; one was a branded product with 48.6% CP and 1.8 mg of TIA/g and the other was obtained from soybeans of US origin that were dehulled and processed in Spain (50.6% CP and 2.4 mg of TIA/g). The experimental design was completely randomized with 6 diets and 6 replicates per treatment. Chicks were fed a commercial diet from 1 to 16 d of age and then their respective experimental diets for 5 d. The diets were based on sucrose and corn starch, with the SBM tested as the only source of protein. At 21 d of age, digesta was collected from the distal ileum and the CAID of nutrients was determined using celite as an indigestible marker. Diets that included the 2 SBM with the greatest CP content had greater CAID of DM (P