Amino acid supplementation during the adaptation period did not affect the standardized ileal digestibility of amino acids in corn and soybean meal fed to pigs.

OBJECTIVE: The objective was to determine the influence of amino acid (AA) supplementation during the adaptation period on the ileal digestibility of crude protein and AA in corn and soybean meal (SBM) fed to pigs. METHODS: Six barrows with an initial body weight of 30.9±2.6 kg fitted with a T-cannula at the distal ileum were assigned to a 6×6 Latin square design with 6 dietary treatments and 6 periods. Two experimental diets contained corn or SBM as the sole AA source and an N-free diet was additionally prepared. For AA supplementation groups, an AA mixture consisted of Gly, Lys, Met, Thr, Trp, Ile, Val, His, and Phe was added to the corn diet and the N-free diet at the expense of cornstarch, and an AA mixture of Lys, Met, and Thr was added to the SBM diet. All diets contained 0.5% of chromic oxide. The 6 experimental diets were fed to the pigs for four and half days, and the 3 diets containing an AA mixture were switched to the respective diets without AA mixture during the following two and half days. Ileal digesta were collected on days 6 and 7. RESULTS: The addition of an AA mixture during the adaptation period increased apparent ileal digestibility of Arg and Trp in corn (p<0.05) but did not affect that in SBM. The addition of an AA mixture during the adaptation period increased apparent ileal digestibility of Pro and Gly regardless of feed ingredient (p<0.05) but did not affect that of other AA. All AA except Pro in corn and SBM were unaffected by the addition of the AA mixture during the adaptation period. CONCLUSION: The addition of amino acids to a low-protein diet during the adaptation period does not affect the standardized ileal digestibility of indispensable amino acids in pigs.

Effects of Drying Methods and Blanching on Nutrient Utilization in Black Soldier Fly Larva Meals Based on In Vitro Assays for Pigs.

The objective was to determine the effects of drying and blanching methods on the nutrient utilization of black soldier fly larva (BSFL; Hermetia illucens) meal by pigs using in vitro assays. Two-step and three-step in vitro assays were employed to simulate the gastrointestinal tract of pigs. Four BSFL meals were prepared using the following pretreatment methods: (1) microwave drying at 80 °C for 32 min, (2) hot-air drying at 60 °C for 17 h, (3) blanching for 5 min in boiling water and hot-air drying at 60 °C for 17 h, and (4) 2% citric acid solution blanching for 5 min in boiling solution and hot-air drying at 60 °C for 17 h. After the drying process, each BSFL was defatted and ground to obtain BSFL meals. The nitrogen (N) concentration in the test ingredients ranged from 8.5 to 9.4%, and the ether extract ranged from 6.9 to 11.5% on an as-is basis. The amino acid (AA) concentration in the BSFL meals ranged from 2.80 to 3.24% for Lys and 0.71 to 0.89% for Met on an as-is basis. Hot-air-dried BSFL meal had a greater in vitro ileal disappearance (IVID) of N compared with microwave-dried BSFL meal (p < 0.05). However, blanched BSFL meals in water or 2% citric acid solution before hot-air drying had a lower (p < 0.05) IVID of N compared with microwave-dried or hot-air-dried BSFL meal. Blanched BSFL meals in water or 2% citric acid solution before hot-air drying showed a lower (p < 0.05) in vitro total tract disappearance of dry matter and organic matter compared with microwave-dried or hot-air-dried BSFL meal. Microwave-dried BSFL meal had a lower (p < 0.05) IVID of indispensable AA, except for His, Lys, Met, and Phe, compared with hot-air-dried BSFL meals. However, blanched BSFL meals in water or 2% citric acid solution before hot-air drying showed a lower (p < 0.05) IVID of indispensable AA compared with microwave-dried or hot-air-dried BSFL meal. In conclusion, hot-air-dried BSFL meal presented greater nutrient utilization compared with microwave-dried BSFL meal for pigs. However, blanching in water or citric acid solution negatively affected the nutrient digestibility of BSFL meal based on in vitro assays.

H9N2-specific IgG and CD4+CD25+ T cells in broilers fed a diet supplemented with organic acids.

Organic acids have long been known for their beneficial effects on growth performance in domestic animals. However, their impact on immune responses against viral antigens in chickens is unclear. The present study aimed to investigate immunological parameters in broilers immunized with a H9N2 vaccine and/or fed a diet containing organic acids (citric, formic, and lactic acids). We allotted 1-day-old broilers into 4 groups: control (C), fed a diet supplemented with organic acids (O), administered a H9N2 vaccine (V), and fed a diet supplemented with organic acids and administered a H9N2 vaccine (OV). Blood and spleen samples were taken at 2, 7 and 14 d post vaccination (DPV). At 14 DPV, total and H9N2-specific IgG levels were significantly lower in the OV group than in the V group. However, it was intriguing to observe that at 2 DPV, the percentage of CD4+CD25+ T cells was significantly higher in the OV group than in the other groups, indicating the potential induction of regulatory T cells by organic acids. In contrast, at 2 DPV, the percentage of CD4+CD28+ T cells were significantly lower in the OV group than in the other groups, suggesting that CD28 molecules are down-regulated by the treatment. The expression of CD28 on CD4+ T cells, up-regulated by the stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin (Iono), was inhibited upon organic acid treatment in OV group. In addition, the proliferation of lymphocytes, stimulated with formalin-inactivated H9N2, was significantly higher in the V group than in the OV group. Alpha 1-acid glycoprotein (AGP) production was significantly lower in the OV group than in the V group, suggesting that the organic acids inhibited the inflammation caused by the vaccination. Overall, induction of regulatory CD4+CD25+ T cells, coinciding with the decrease of H9N2-specific antibodies, was observed in broilers fed organic acids.

Angiotensin-I converting enzyme inhibitory and antioxidant activities of egg protein hydrolysates produced with gastrointestinal and nongastrointestinal enzymes.

Egg is a well-known rich source of bioactive peptides. In this study, egg protein (egg white and egg yolk proteins) hydrolysates were produced with gastrointestinal enzymes (pepsin and pancreatin) or nongastrointestinal enzymes (thermolysin and alcalase), and fractionated by ultrafiltration and cation exchange chromatography. Angiotensin-I converting enzyme (ACE) inhibitory and antioxidant activities, amino acid composition and molecular weight distribution were studied, and the physicochemical properties were related with the bioactivities. Our results showed that egg protein hydrolysates produced with non-GI enzymes (thermolysin and alcalase) showed significantly higher ACE inhibitory activity, whereas similar or even lower antioxidative activities, than those of hydrolysates produced with GI enzymes. ACE-inhibitory activity significantly correlated with the amino acid composition, especially the proportion of positively charged amino acid, whereas antioxidant activities correlated with the proportion of low molecular weight peptides under 500 Da. Understanding the relationship between the bioactivities and physicochemical properties of the hydrolysates/fractions is important to facilitate the development technologies for preparing fractions with improved bioactivities.

Identification of novel antioxidative peptides derived from a thermolytic hydrolysate of ovotransferrin by LC-MS/MS.

Ovotransferrin is a glycoprotein well-known for its iron-binding property. Ovotransferrin was reported to have antioxidative properties, but the presence of antioxidant peptides within the protein has not been reported. The purpose of the study was to characterize the antioxidant peptides within ovotransferrin. Ovotransferrin was sonicated and hydrolyzed by thermolysin, and peptides from the hydrolysate were fractionated by ion-exchange fast protein liquid chromatography and reversed-phase high-performance liquid chromatography. Fourteen peptides derived from ovotransferrin were characterized using LC-MS/MS, and their oxygen radical absorbance capacity (ORAC) values were determined using synthetic peptides. Two tetrapeptides (Trp-Asn-Ile-Pro and Gly-Trp-Asn-Ile) showed the highest antioxidant activity. Interestingly, the addition of amino acid residues to either the N or C terminus of the two peptides decreased the antioxidant activity, suggesting that the motif of Trp-Asn-Ile is responsible for the high antioxidant activity.