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The objective was to test the hypothesis that feeding intact protein from soybean meal (SBM) to growing pigs instead of crystalline amino acids (AA) increases nitrogen (N) retention, digestible energy (DE), and metabolizable energy (ME). A control corn-SBM diet and three diets, in which the inclusion rate of SBM was reduced and 3, 4, or 5 crystalline AA (i.e., Lys, Met, Thr, Trp, Val) were added, were formulated. The concentration of standardized ileal digestible AA was constant among diets, but crude protein was reduced as crystalline AA were added. Pigs were limit fed at 3.2 times the ME requirement for maintenance. Forty pigs (initial body weight = 20.5 kg; SD = 2.4) were allotted to the 4 diets using a randomized complete block design with 2 blocks of 20 pigs with five pigs per diet in each block. Pigs were housed in metabolism crates with pans and screens that allowed for quantitative collection of feces and urine for 4 d after 5 d of adaptation. Samples of diets, feces, and urine were analyzed for gross energy (GE) and N. The statistical model included diet as fixed effect and block as random effect, and pig was the experimental unit. Contrasts coefficients were used to determine linear and quadratic effects of reducing dietary protein. Results indicated that apparent total tract digestibility (ATTD) of dry matter (DM) decreased (quadratic, P= 0.027) and ATTD of GE tended to decrease (quadratic, P= 0.076; Table 1) as SBM inclusion was reduced in the diets. Absorbed N, retained N (g/d), and ATTD of N were decreased (linear, P< 0.001) as SBM decreased in diets, but retention of N (% of intake and % of absorbed) increased (linear, P< 0.001) as SBM decreased in diets. The DE decreased (linear, P= 0.007) as SBM decreased in diets, whereas SBM had no effect on ME. Dietary SBM also had no effect on ME to GE ratio, but ME to DE increased (linear, P= 0.008) by reducing SBM in diets. In conclusion, diets containing intact protein from SBM had greater ATTD of GE and N, and greater DE, but reduced N retention rate when compared with diets containing crystalline AA. However, daily protein retention could not be maintained when crystalline AA rather than SBM were used to furnish the digestible AA in the diets, which may have negative consequences on carcass quality.

Inclusion of high protein corn protein (HPCP) in diets for weanling pigs may result in diets with excess Leu being formulated, which may reduce growth performance. However, it was hypothesized that the negative effect of using HPCP in diets for weanling pigs may be overcome if diets are fortified with crystalline Val, Trp, and (or) Ile. A total of 320 weanling pigs were randomly allotted to 10 dietary treatments in a randomized complete block design. Day 1 to 14 was phase 1 and d 15 to 28 was phase 2. Within each phase, a corn-soybean meal control diet and 2 diets based on corn and 10% HPCP or corn and 20% HPCP were formulated. Seven additional diets were formulated by adding Val, Ile, Trp, Val and Ile, Val and Trp, Ile and Trp, or Val, Ile, and Trp to the diet with 20% HPCP. Fecal scores were recorded every other day. Blood samples were collected on d 14 and d 28. Data were analyzed using the PROC MIXED of SAS; diet was the fixed effect and block and replicate within block were random effects. Inclusion of 10 or 20% HPCP in diets reduced (P< 0.05) final body weight (BW) on d 28, and also reduced (P< 0.05) average daily gain (ADG) and average daily feed intake (ADFI) in phase 2 and for the overall experiment (Table 1). However, pigs fed the HPCP diet supplemented with Val, Ile, and Trp had a greater (P< 0.05) final BW and ADG in phase 2 and for the overall experiment than pigs fed the HPCP diets without AA or with Ile, Trp, or Ile and Trp, and results for this diet were not different from results for the control diet. Fecal scores in phase 2 were reduced (P< 0.05) if 20% HPCP was included in the diets except if Ile and Val were also included (Table 2). On d 28, pigs fed the diet with 20% HPCP and only Val, Val and Trp, or Val, Trp, and Ile had reduced (P< 0.01) blood urea N compared with pigs fed the control diet or the other HPCP-based diets, and pigs fed the control diet and the diet with 20% HPCP and Val, Ile and Trp had a greater (P< 0.05) albumin concentration than pigs fed the other diets (Table 3). Thus, the increased catabolism of Val, and reduced Trp transport into the brain that are caused by excess Leu from HPCP may be overcome by adding Val, Ile, and Trp to HPCP-based diets. In conclusion, up to 20% HPCP may be included in diets for weanling pigs without affecting growth performance or blood characteristics if diets are fortified with extra Val, Ile, and Trp.

The objective was to test the hypothesis that feeding intact protein from soybean meal (SBM) instead of crystalline amino acids (AA) does not affect growth performance, protein synthesis, intestinal morphology, or immune response of growing pigs. A control corn-SBM diet was used. Three additional diets were formulated by reducing the inclusion rate of SBM and adding 3, 4, or 5 crystalline AA (i.e., Lys, Met, Thr, Trp, Val) to the diets, which resulted in reducing the protein concentration from 20.0% to 13.4%. All diets were formulated to meet requirements for standardized ileal digestible indispensable AA. A total of 176 pigs [initial body weight (BW) = 32.2 kg; SD = 4.2] were used. On d 1, 16 randomly chosen pigs were euthanized and body nutrient composition was determined. The remaining 160 pigs were allotted to the 4 diets using a randomized complete block design with 4 pigs per pen and 10 replicate pens per diet. Starting BW was the blocking factor. Individual pig BW and feed consumption were recorded. On d 28, one pig per pen was slaughtered and blood, carcass, and viscera were collected and analyzed for N, fat, and energy to calculate deposition in the body. Ileal mucosa, ileum and colon tissue and digesta were analyzed for blood characteristics, cytokines, tissue morphology, ammonia, and gene expression. Contrasts coefficients were used to determine linear and quadratic effects of reducing dietary protein. Results indicated that average daily gain, average daily feed intake, gain to feed ratio, carcass characteristics, and protein, lipid, and energy depositions were not affected by reducing SBM and increasing crystalline AA in diets (Table 1). However, energy efficiency tended to decrease (quadratic, P= 0.083) by reducing dietary protein. Blood urea N was reduced (linear, P< 0.001) as dietary protein was reduced, but blood total protein was not affected by dietary treatment. Cytokines, ileal and jejunal morphologies, and gene abundance of AA transporters in the ileal mucosa were not affected by dietary protein. Ammonia concentrations in ileal digesta increased and then decreased (quadratic, P= 0.043) and colon digesta tended to increase and then decrease (quadratic, P= 0.074) as dietary protein was reduced. Bacteria protein in colon digesta was reduced (linear, P= 0.030) by reducing dietary protein. In conclusion, providing AA from intact protein from SBM or from crystalline AA did not affect growth performance, intestinal morphology, and immune response of pigs. However, SBM in diets can provide energy that may be utilized more efficiently than energy from diets with less SBM and crystalline AA. Further research is suggested to elucidate if SBM improves utilization of other nutrients in diets for pigs.

Diet formulation in animal production has traditionally relied on a limited number of feed ingredients. Cassava is a starchy tuber crop grown in tropical and subtropical areas that can be used as an alternative ingredient in animal diets due to increasing cereal grain prices and their impact on feed costs. Therefore, information about the chemical composition of cassava-based feed ingredients is needed to formulate diets. The objective of this study was to determine the chemical composition of cassava-based feed ingredients and test the hypothesis that there is variation in chemical composition among cassava products originating from different South-East Asian countries. Sources of dried peeled cassava roots, unpeeled cassava roots, cassava chips, cassava meal, high ash cassava meal, and cassava residue were used. All ingredients were analyzed for dry matter, gross energy, N, amino acids (AA), acid hydrolyzed ether extract, ash, minerals, starch, insoluble dietary fiber, soluble dietary fiber, and total dietary fiber. Peeled cassava roots, unpeeled cassava roots, cassava chips, and cassava meal were also analyzed for sugars. Data were analyzed by ANOVA to test statistical differences among all cassava-based ingredients, and an alpha value of 0.05 was used to assess significance among means. Results indicated that high ash cassava meal had greater (P< 0.05) dry matter and ash, but less (P< 0.05) starch and gross energy than all other cassava products (Table 1). Peeled cassava roots, unpeeled cassava roots, and cassava chips had greater (P< 0.05) starch than the other cassava ingredients. Cassava residue had greater (P< 0.05) Lys, insoluble, soluble, and total dietary fiber concentrations compared with the other cassava products, but Trp and Glu were greater (P< 0.05) in peeled cassava roots, cassava chips, and cassava meal samples compared with the other ingredients. The concentration of most minerals was greater (P< 0.05) in high ash cassava meal than in the other cassava products. In conclusion, cassava-based ingredients sold as peeled roots, unpeeled roots, chips, or meal have chemical compositions that are not different, and peeling seems to have little impact on chemical composition. High ash cassava meal has less nutritional quality compared with other cassava products due to low starch and gross energy. The high fiber content in cassava residue makes this ingredient more suitable for ruminants and sows than for younger pigs or poultry.