Biological Function of Antimicrobial Peptides on Suppressing Pathogens and Improving Host Immunity.

The emergence of drug-resistant genes and concerns about food safety caused by the overuse of antibiotics are becoming increasingly prominent. There is an urgent need for effective alternatives to antibiotics in the fields of livestock production and human medicine. Antimicrobial peptides can effectively replace antibiotics to kill pathogens and enhance the immune functions of the host, and pathogens cannot easily produce genes that are resistant to them. The ability of antimicrobial peptides (AMPs) to kill pathogens is associated with their structure and physicochemical properties, such as their conformation, electrical charges, hydrophilicity, and hydrophobicity. AMPs regulate the activity of immunological cells and stimulate the secretion of inflammatory cytokines via the activation of the NF-κB and MAPK signaling pathways. However, there are still some limitations to the application of AMPs in the fields of livestock production and human medicine, including a restricted source base, high costs of purification and expression, and the instability of the intestines of animals and humans. This review summarizes the information on AMPs as effective antibiotic substitutes to improve the immunological functions of the host through suppressing pathogens and regulating inflammatory responses. Potential challenges for the commercial application of AMPs in animal husbandry and human medicine are discussed.

Net energy and its establishment of prediction equations for wheat bran in growing pigs.

OBJECTIVE: The objective of this experiment was to determine the net energy (NE) value of 6 wheat bran and 1 wheat shorts by indirect calorimetry and establish the NE prediction equations of wheat bran fed to growing barrows. METHODS: Forty-eight growing barrows (28.5±2.4 kg body weight) were allotted in a completely randomized design to 8 dietary treatments that included a corn-soybean meal basal diet, 6 wheat bran diets and 1 wheat shorts diet. The inclusion level of wheat bran or wheat shorts in diets is 30%. RESULTS: The addition of wheat bran reduced the apparent total tract digestibility (ATTD) of nutrients (p<0.05). The ATTD of gross energy, crude protein (CP) and dry matter (DM) in the wheat shorts were greater than that in the wheat bran. Addition of wheat bran or wheat shorts had no effect on total heat production and fasting heat production. The NE of wheat bran was negatively correlated with neutral detergent fiber (r = -0.84; p<0.05) and acid detergent fiber (r = -0.83; p<0.05), while it was positively correlated with CP (r = 0.92; p<0.01). The NE values of wheat bran ranged from 6.79 to 8.15 MJ/kg DM, and the NE value of wheat shorts was 12.47 MJ/kg DM. The ratio of NE to metabolizable energy for wheat bran fed to growing pigs was from 66.0% to 71.7%, whereas the value for wheat shorts was 83.7%. CONCLUSION: The NE values of wheat bran ranged from 6.79 to 8.15 MJ/kg DM, and the NE value of wheat shorts was 12.47 MJ/kg DM. The NE value of wheat bran can be well predicted based on energy content and proximate analysis.

Effects of Defatted Rice Bran Inclusion Level on Nutrient Digestibility and Growth Performance of Different Body Weight Pigs.

This study was conducted to determine the effects of low-protein diet prepared with different levels of defatted rice bran (DFRB) and weight stages on growth performance and nutrient digestibility of growing-finishing pigs. The animal experiment included three stages. A total of 240 growing pigs with an initial body weight of 28.06 ± 8.56 kg for stage 1 were allocated to five diets including one control group and four DFRB diets supplemented with 2.5%, 5%, 7.5% and 10% DFRB, respectively. The 192 crossbred pigs with initial body weights of 55.03 ± 7.31 kg and 74.55 ± 9.10 kg were selected for stage 2 and stage 3, respectively. Pigs were allocated to four diets including one control group and three DFRB diets supplemented with 10%, 15% and 20% DFRB, respectively. The results showed that with the increase in DFEB intake, the gain: feed was linearly increased (p < 0.05), and the average daily feed intake tended to linearly decrease (p = 0.06) in stage 1. Except for the apparent total tract digestibility (ATTD) of acid detergent fiber (ADF) in stage 3, levels of DFRB had significant effects on the ATTD of gross energy (GE), dry matter (DM), ash, neutral detergent fiber (NDF) and ADF in three weight stages. In stage 1, with the increase in levels of DFRB, the ATTD of NDF and hemicellulose were firstly increased and then decreased (p < 0.01). In stage 2, with the increasing levels of DFRB, the ATTD of DM, ash and cellulose were firstly increased and then decreased (p < 0.01). In stage 3, the ATTD of GE, DM, ash, NDF and hemicellulose decreased linearly with the increase in levels of DFRB (p < 0.01). Collectively, DFRB could be used as a replacement for corns and soybean meal, and weight stage is important to consider when adjusting the additive proportion.

Evaluation on Net Energy of Defatted Rice Bran from Different Origins and Processing Technologies Fed to Growing Pigs.

The study was conducted to determine and compare the net energy (NE) of defatted rice bran (DFRB) from different sources and different processing technology fed to growing pigs using indirect calorimetry. Thirty-six growing barrows (30.7 ± 3.9 kg) were randomly allotted to 1 of 6 diets with 6 replicate pigs per diet. Diets included a corn-soybean meal basal diet and 5 test diets containing 30% DFRB, respectively. These five samples come from 4 different provinces (i.e., Heilongjiang, Jiangsu, Jilin, and Liaoning province within China) and two of them with the same origin but different processing technologies (i.e., extruded or pelleted). During each period, pigs were kept individually in metabolism crates for 21 days, including 14 days to adapt to the diets. On day 15, pigs were transferred to the open-circuit respiration chambers for adaptation, and the next day were ready to determine daily total heat production (HP) and were fed 1 of the 6 diets at 2.3 MJ metabolizable energy (ME)/kg body weight (BW)0.6/day. Total feces and urine were collected for the determination of digestible energy (DE) and ME and daily total HP was measured from day 16 to day 20 and fasted on day 21 for the measurement of fasting heat production (FHP). The NE contents of extruded DFRB from different provinces were within the range of values (8.24 to 10.22 MJ/kg DM). There is a discrepancy of approximately 10.01% in the NE content between the DFRB origins. The NE contents of extruded DFRB and pelleted DFRB from the same province were 8.24 vs. 6.56 MJ/kg DM. Retained energy (RE) and FHP of diets containing extruded DFRB and pelleted DFRB were 1105 vs. 892 kJ/kg BW0.6/day and 746 vs. 726 kJ/kg BW0.6/day respectively, and those in extruded DFRB from different origins were within the range of values (947 to 1105 kJ/kg BW0.6/day and 726 to 755 kJ/kg BW0.6/day, respectively). In conclusion, NE values are affected by origin and processing technology of DFRB.

Effects of different defatted rice bran sources and processing technologies on nutrient digestibility in cannulated growing pigs.

The objective of this study was to evaluate the effects of different defatted rice bran (DFRB) sources and processing technologies on nutrient digestibility in different intestinal segments of pigs. Nine barrows with T-cannula in the distal ileum were randomly allotted to nine different sources in which oil was pressed extracted for seven sources and was solvent extracted for two sources. The experiment contained 6 periods of 12 d, including 8 d for diet adaptation, 2 d for fecal collection, and 2 d for digesta collection. The apparent ileal digestibility (AID) of dry matter (DM), ash, total dietary fiber (TDF), insoluble dietary fiber (IDF), neutral detergent fiber (NDF), acid detergent fiber (ADF), and hemicellulose in different sources of DFRB was quite variable. There were no differences in the AID of dietary gross energy (GE), organic matter (OM), ether extract (EE), crude protein (CP), and soluble dietary fiber (SDF) between different sources of DFRB. There were no differences in the AID of dietary EE, TDF, IDF, and hemicellulose between different processing technologies. Pressed DFRBs have greater (P < 0.05) average AID of dietary GE, DM, ash, OM, CP, SDF, and NDF and lower (P < 0.01) ADF compared with solvent-extracted DFRBs. The apparent total tract digestibility (ATTD) of most of the dietary nutrients, except for the ATTD of dietary EE, SDF, and hemicellulose, significantly varied in different sources of DFRB (P < 0.05). In addition, pressed DFRB had greater (P < 0.05) ATTD of dietary SDF, NDF, ADF, and hemicellulose compared with solvent-extracted DFRB. The apparent hindgut digestibility (AHD) of dietary DM, SDF, NDF, and ADF significantly varied (P <0.05) in different sources of DFRB. Exception with DM, there are no differences in the AHD of nutrients digestibility between pressed DFRB and solvent-extracted DFRB. In conclusion, DFRB in different sources and processing technologies with different physicochemical properties had different effects on nutrient digestibility in the foregut and hindgut of pigs.

Prediction of net energy values in expeller-pressed and solvent-extracted rapeseed meal for growing pigs.

OBJECTIVE: The objective of this study was to determine net energy (NE) of expeller-press (EP-RSM) and solvent-extracted rapeseed meal (SE-RSM) and to establish equations for predicting the NE in rapeseed meal (RSM) fed to growing pigs. METHODS: Thirty-six barrows (initial body weight [BW], 41.1±2.2 kg) were allotted into 6 diets comprising a corn-soybean meal basal diet and 5 diets containing 19.50% RSM added at the expense of corn and soybean meal. The experiment had 6 periods and 6 replicate pigs per diet. During each period, the pigs were individually housed in metabolism crates for 16 days which included 7 days for adaption to diets. On day 8, pigs were transferred to respiration chambers and fed their respective diet at 2,000 kJ metabolizable energy (ME)/kg BW0.6/d. Feces and urine were collected, and daily heat production was measured from day 9 to 13. On days 14 and 15, the pigs were fed at 890 kJ ME/kg BW0.6/d and fasted on day 16 for evaluation of fasting heat production (FHP). RESULTS: The FHP of pigs averaged 790 kJ/kg BW0.6/d and was not affected by the diet composition. The NE values were 10.80 and 8.45 MJ/kg DM for EP-RSM and SE-RSM, respectively. The NE value was positively correlated with gross energy (GE), digestible energy (DE), ME, and ether extract (EE). The best fit equation for NE of RSM was NE (MJ/kg DM) = 1.14×DE (MJ/kg DM)+0.46×crude protein (% of DM)-25.24 (n = 8, R2 = 0.96, p<0.01). The equation NE (MJ/kg DM) = 0.22×EE (% of DM)-0.79×ash (% of DM)+14.36 (n = 8, R2 = 0.77, p = 0.018) may be utilized to quickly determine the NE in RSM when DE or ME values are unavailable. CONCLUSION: The NE values of EP-RSM and SE-RSM were 10.80 and 8.45 MJ/kg DM. The NE value of RSM can be well predicted based on energy content (GE, DE, and ME) and proximate analysis.

Comparison of regression and fat-free diet methods for estimating ileal and total tract endogenous losses and digestibility of fat and fatty acids in growing pigs.

An experiment was conducted to 1) compare the regression and fat-free diet methods for estimating total or basal endogenous losses of fat (ELF) and fatty acids (ELFA) and true digestibility (TD) or standardized digestibility (SD) of fat and fatty acids in growing pigs and 2) compare these estimated values at the end of the ileum and over the entire intestinal tract. Ten barrows (initial body weight: 45.1 ± 2.8 kg) were surgically fitted with a T-cannula in the distal ileum and allotted to one of five experimental diets in a three-period Youden Square design. A fat-free diet was formulated using cornstarch, soy protein isolate, and sucrose. Four oil-added diets were formulated by adding four levels of soybean oil (2%, 4%, 6%, and 8%) to the fat-free basal diet at the expense of cornstarch. All diets contained 26% sugar beet pulp and 0.40% chromic oxide. Results indicated that there were no differences between true ileal digestibility (TID) of fat and true total tract digestibility (TTTD) of fat when pigs were fed soybean oil. The TID of C18:0 and total saturated fatty acids (TSFA) was greater than TTTD (P < 0.05). The total ELF at the end of the ileum were not different from that over the entire intestinal tract. In addition, total endogenous losses of C18:0 and TSFA were greater for the entire intestinal tract than at the end of the ileum, whereas total endogenous losses of C18:2 and total unsaturated fatty acids were just the opposite. Similar results were observed for basal ELF and ELFA. As the inclusion level of soybean oil increased, apparent digestibility (AD) of fat and fatty acids increased linearly (P < 0.05) except for apparent ileal digestibility of C18:0. However, SD of fat and fatty acids was not influenced by the inclusion level of soybean oil. Estimation of ELF and ELFA observed by the regression and fat-free diet methods did not differ when measured at the end of the ileal or total tract. There were no differences between the estimations of TD and SD of fat and fatty acids for soybean oil. Collectively, the estimation of TD or SD of fat can be measured over the entire intestinal tract, whereas the ileal analysis method should be used to determine the ELF, ELFA, and TD or SD of fatty acids. Correcting AD for basal ELF and ELFA can accurately estimate SD values of fat and fatty acids.

Oat bran and wheat bran impact net energy by shaping microbial communities and fermentation products in pigs fed diets with or without xylanase.

BACKGROUND: Dietary fiber can be fermented in gut of pigs and the end products of fermentation were short-chain fatty acids (SCFA). The SCFA had positive effects on gut bacteria and host immune system. In addition, SCFA can provide a part of available energy for pigs. However, there were limited reports on the relationship between dietary fiber, gut bacteria, and energy metabolism. Therefore, this study investigated how dietary fiber and enzyme addition impacted energy metabolism by acting on the microbial community and SCFA. METHODS: Wheat bran (WB) was added to the corn-soybean meal-based diet at the levels of 12% and 27%, and oat bran (OB) at 15% and 36%. One of each diet was supplemented with or without 5000 U/kg feed of xylanase, so a total of 10 diets were allotted to 60 growing pigs (initial body weight: 27.2 ± 1.2 kg) using a randomized complete block design. The experiment was conducted in 10 consecutive periods using 6 similar open-circuit respiration chambers. Each pig was used for one 20-day period. During each period, six pigs were allowed 14 d to adapt to the diets in metabolic cages followed by 6 d (from d 15 to d 20) in respiration chambers to measure heat production (HP). RESULTS: Pigs fed 36% OB diets had greater (P <  0.05) nutrient digestibility and net energy (NE) values compared to those fed 27% WB diets. Apparent digestibility coefficients of dry matter (DM) and crude protein (CP) were lower (P < 0.05) in pigs fed 27% WB diets compared with those fed 12% WB diets. Enzyme addition improved (P < 0.05) the NE values (11.37 vs. 12.43 MJ/kg DM) in diets with 27% WB. Supplementation of xylanase did not affect NE values for basal diets, OB diets and 12%WB diets. Compared with diets with 36% OB, pigs fed 27% WB-based diets excreted more total SCFA, acetate and propionate (expressed as g/kg feed DM) in fecal samples of pigs (P < 0.05). Pigs in the WB diets had greater proportion of phylum Bacteroidetes while phylum Firmicutes were greater in pigs fed OB diets (P < 0.05). Pigs fed WB diets had greater (P < 0.05) abundance of Succinivibrio and Prevotella, which were associated with fiber degradation and SCFA production. CONCLUSION: Our results indicated diets supplied by high level of OB or WB promote the growth of fiber-degrading bacteria. The differences in fiber composition between WB and OB led to differences in nutrient digestibility and bacterial communities, which were ultimately reflected in energy metabolism. Enzyme supplementation improved nutrient digestibility as well as NE values for 27% WB diets but not for other diets, which indicated that effects of enzyme were related to type and level of dietary fiber in diets.

Effects of particle size and lipid form of corn on energy and nutrient digestibility in diets for growing pigs.

OBJECTIVE: Two experiments were conducted to evaluate the effects of corn particle size and lipid form on the apparent total tract digestibility (ATTD) of energy and nutrients in diets for growing pigs. METHODS: In Exp. 1, thirty barrows (initial body weight [BW], 53.1±3.9 kg) were allotted to 1 of 5 diets formulated with 96.9% corn ground to 441, 543, 618, 659, and 768 µm, respectively. In Exp. 2, thirty-six barrows (initial BW, 54.7±3.6 kg) were allotted to 1 of 6 diets formulated by including 2% or 15% corn germ (CG 2 or CG 15), 1% or 6% corn oil (CO 1 or CO 6), 1% CO+2% corn germ meal (CO 1+CGM 2), or 6% CO+15% corn germ meal (CO 6+CGM 15), respectively. RESULTS: The ATTD of gross energy (GE) and the digestible energy (DE) in diet and corn grain linearly decreased as the corn particle size increased (p<0.05) from 441 to 768 µm. Particle size had a quadratic effect (p<0.05) on the ATTD of neutral detergent fiber and acid detergent fiber in diets, and which firstly increased and then decreased as the corn particle size increased from 441 to 618 µm and 618 to 768 µm, respectively. The ATTD of GE, ether extract (EE), and the DE in CO 1 diet and CO 6 diet was greater (p<0.05) than that in CG 2 diet and CG 15 diet, respectively. The ATTD of EE in CO 6 diet and CO 6+CGM 15 diet was greater (p<0.05) than that in CO 1 diet and CO 1+CGM 2 diet. CONCLUSION: Less than 618 µm was recommended for corn particle size in growing pig's diet and extracted lipid had greater digestibility than the intact lipid in corn. Higher concentration of extracted CO had greater digestibility of EE compared with lower concentrations of CO diet.

Endogenous Losses of Fat and Fatty Acids in Growing Pigs Are Not Affected by Vegetable Oil Sources but by the Method of Estimation.

An experiment was conducted to determine the effect of oil sources with differing degrees of fatty acid saturation on endogenous losses of fat (ELF) and fatty acids (ELFA) in growing pigs, in which endogenous losses were estimated by two methods. Sixty-eight growing barrows (initial body weight 31.13 ± 4.44 kg) were randomly allotted to a completely randomized design with 17 diets. Sixteen added-oil diets were formulated by adding four levels (2%, 4%, 6% and 8%) of palm oil (PO), soybean oil (SBO), flaxseed oil (FSO) and rapeseed oil (RSO) to a diet poor in fat, respectively. One fat-free diet was formulated from cornstarch, soy protein isolate and sucrose. All diets contained chromic dioxide (0.4%) as an indigestible marker. Results indicated that, according to the regression equations, the amounts of ELF in PO, SBO, FSO and RSO were 6.28, 5.30, 4.17 and 4.84 g/kg of dry matter intake (DMI), respectively. The true total tract digestibility of fat was greater (p < 0.05) for FSO and RSO than for PO, and the ELFA were different from 0 only for C16:0, C18:0 and C18:1 in FSO, and C16:0 and C18:0 in RSO (p < 0.05). The estimated values for ELF and ELFAs in pigs fed PO, SBO, FSO or RSO were not different. The amount of ELF determined by the fat-free diet method was 2.60 g/kg DMI, and the amounts of C16:0, C18:0, C18:1 and C18:2 in ELFAs were 0.28, 0.26, 0.03 and 0.02 g/kg DMI, respectively. The fat-free diet method had lower ELF and ELFA values compared with the regression method (p < 0.01). Collectively, dietary vegetable oil sources do not affect estimation of ELF and ELFA, but different evaluation methods lead to varying estimates of endogenous losses in pigs.

Effects of dietary fibre level and body weight of pigs on nutrient digestibility and available energy in high-fibre diet based on wheat bran or sunflower meal.

The objectives of this study were (a) to investigate the effect of body weight (BW) on available energy in fibre-rich diets containing two NDF levels; and (b) to evaluate the effect of fibre type and NDF level on AA digestibility. In Exp. 1, barrows (24 at 33.4 ± 1.1 kg; 24 at 86.8 ± 3.3 kg) were randomly allotted to 4 diets containing a high protein basal (HPB), a low protein basal (LPB), 70% HPB + 30% wheat bran (WB) (HPB-WB) and 70% LPB + 30% sunflower meal (SFM) (LPB-SFM). In Exp. 2, barrows (24 at 33.5 ± 1.8 kg; 24 at 87.0 ± 3.8 kg) were randomly allotted to 4 diets containing no SFM with 12% NDF (SFM0LF), no SFM with 16% NDF (SFM0HF), 24% SFM with 12% NDF (SFM24LF) and 24% SFM with 16% NDF (SFM24HF). In Exp. 3, twelve barrows (35.5 ± 3.4 kg) fitted with T-cannulas were allotted to two 6 × 4 Youden square design with 6 diets (4 same diets as in Exp. 2 and 2 nitrogen-free diets). The concentration of DE, ME and ATTD of GE, CP, NDF and ADF in diets was greater (p < .01) when fed to 90 kg pigs compared with 30 kg pigs. The ME in ingredients was not affected by BW. The ATTD of NDF was negatively correlated with the CF (r = -.98; p < .01), ADF (r = -.99; p < .01) and ADL content (r = -.96; p < .01). The ME of diets was negatively correlated with the ATTD of CF (r = -.98; p < .01). The addition of SFM increased the standardized ileal digestibility (SID) of Met (p < .05). In conclusion, diets rich in fibre had different nutritional values at different pig weight stages. The AA digestibility depends mainly on chemical composition of diets.

Net energy content of five fiber-rich ingredients fed to pregnant sows.

The present study was conducted to determine the net energy (NE) values and energy efficiency of wheat bran (WB), sugar beet pulp (SBP), corn gluten feed (CGF), soybean hulls (SBH), and defatted rice bran (DFRB) fed to pregnant sows. Thirty-six multiparous pregnant sows were randomly assigned to six dietary treatments with six replicates per treatment. Each period lasted for 21 days including 14 days for adaptation. On day 15, sows were moved into respiration chambers for heat production (HP) measurement and provided feed at 544 kJ/kg BW0.75 /day. On day 20, sows were fasted to measure the fasting heat production (FHP). Experimental diets included corn-soybean meal basal diet and five diets containing 29.20% WB, SBP, CGF, SBH, and DFRB, respectively. Results showed that inclusion of WB, SBP, CGF, SBH, and DFRB to basal diet decreased (p < 0.05) the apparent total tract digestibility of energy and nutrients. The average adjusted total HP and FHP were 418 kJ/kg BW0.75 /day and 326 kJ/kg BW0.75 /day, respectively. The average NE:ME ratio of experiment diets was 82.5%. In conclusion, the NE values of WB, SBP, CGF, SBH, and DFRB were 9.05, 8.59, 8.37, 7.64, and 7.93 MJ/kg DM, respectively.

Available energy and amino acid digestibility of yellow dent corn fed to growing pigs1.

Two experiments were conducted to determine the DE and ME as well as the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of CP and AA in corn fed to growing pigs. All corn was yellow dent corn collected from different areas in China. In Exp. 1, 60 crossbred barrows (Duroc × Landrace × Yorkshire; 40.7 ± 3.5 kg BW) were randomly allotted to 1 of 10 diets to determine the DE and ME of corns. Diets were formulated to contain 96.8% of 1 of the 10 corn samples and 3.2% of other microingredients. In Exp. 2, 11 crossbred barrows (Duroc × Landrace × Yorkshire; 30.5 ± 2.3 kg) fitted with a T-cannula at the distal ileum were assigned to a 6 × 11 Youden square design with 6 periods and 11 diets. Diets included a N-free diet based on cornstarch and sucrose and 10 test diets formulated with 96.6% 1 of the 10 corns as the sole source of AA. Chromic oxide (0.3%) was added to each diet as an indigestible marker for calculating the AA digestibility. On a DM basis, the starch, ether extract (EE), CP, NDF, and ADF contents of corns averaged 74.05% (69.98 to 78.59%), 3.83% (2.04 to 4.73%), 9.63% (7.74 to 10.43%), 10.80% (10.27 to 11.46%), and 2.27% (2.03 to 2.57%), respectively. The CV of EE, CP, and ADF was 22.59, 8.22, and 8.21%, respectively. The DE and ME of corns averaged 4,087 and 3,981 kcal/kg, respectively, and ranged from 3,999 to 4,161 kcal/kg and from 3,898 to 4,067 kcal/kg, respectively. The DE and ME values were positively correlated (P < 0.05) with the EE content. Optimal prediction equations of ME were ME = 940.35 + (0.72 × DE) + (21.88 × EE) (R2 = 0.94) or ME = 1,051.50 + (0.82 × DE) - (282.05 × ash) (R2 = 0.99). In Exp. 2, significant differences (P < 0.05) were observed in the SID of Arg, His, Phe, Ala, Pro, Cys, and Tyr. The SID of Lys (average 73.79%), Met (average 87.32%), and Thr (average 80.06%) ranged from 61.45 to 78.47%, from 74.09 to 90.91%, and from 79.19 to 85.79%, respectively. The standardized ileal digestible Met was positively correlated (P < 0.01) with the Met and CP contents. The obtained prediction equations were standardized ileal digestible Met = 31.34 + (3.43 × CP) + (116.04 × Met) and standardized ileal digestible Met = 104.92 + (294.71 × Met) - (7.03 × NDF). In conclusion, sources had an effect on the energy values and ileal digestibility of most AA in corn. The ME can be predicted by the DE combined with either the EE or ash content. The AA concentrations and SID of AA in corn varied largely.

Net energy of oat bran, wheat bran, and palm kernel expellers fed to growing pigs using indirect calorimetry.

The objectives of this experiment were to (a) determine the effects of fiber increase in diets on heat production (HP), (b) determine the net energy (NE) of oat bran (OB), wheat bran (WB), and palm kernel expellers (PKE) fed to growing pigs using indirect calorimetry (IC). Twenty-four growing barrows (29.2 ± 2.6 kg) were randomly allotted to one of four diets with six replicate pigs per diet. Diets included a corn-soybean meal basal diet and three test diets containing 30% OB, WB or PKE, respectively. During each period, pigs were individually housed in metabolism crates for 20 days, including 14 days to adapt to the diets. On day (d) 15, pigs were transferred to the open-circuit respiration chambers for determination of daily total HP and were fed one of the four diets at 2.3MJ ME/kg body weight (BW)0.6 /day. Total feces and urine were collected for the determination of digestible energy (DE) and metabolizable energy (ME) and daily total HP was measured from d 15 to d 19 and fasted on day 20 for the measurement of fasting heat production (FHP). The apparent total tract digestibility (ATTD) of dry matter (DM), gross energy (GE), and organic matter (OM) were greater (p < 0.01) in pigs fed the basal diet compared with those fed the test diets. The ATTD of neutral detergent fiber (NDF) was lower (p < 0.01) in pigs fed the WB diet compared with those fed the basal, OB, or PKE diets. The ATTD of ether extract (EE) in pigs fed the PKE diet was greater (p < 0.01) compared with those fed the other diets. The average total HP and FHP in pigs fed the four diets were 1261 and 787 kJ/kg BW0.6 /d, respectively, and were not significantly affected by diet characteristics. The NE:ME ratio for diets ranged from 78.1 to 80.9%. The NE contents of OB, WB, and PKE were 10.93, 7.47, and 8.71 MJ/kg DM, respectively.

Available energy and amino acid digestibility of defatted rice bran fed to growing pigs.

This study was conducted to determine and compare available energy and apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of CP and AA in 9 samples of defatted rice bran (DFRB) fed to growing pigs and to generate prediction equations for DE and ME based on chemical analysis. In Exp. 1, 60 crossbred growing pigs (Duroc × Landrace × Yorkshire; 40.7 ± 3.5 kg BW) were fed 1 of 10 diets in a completely randomized design to determine the available energy of DFRB. The diets included a corn-soybean meal-basal diet and 9 experimental diets formulated by replacing the corn and soybean meal with 29.16% DFRB. In Exp. 2, 6 growing pigs (initial BW = 28.5 ± 2.8 kg) were surgically equipped with a T-cannula in the distal ileum and arranged in a 6 × 6 Latin square design with 6 diets and 6 periods. The diets included an N-free diet based on cornstarch and sucrose and 5 experimental diets containing 60% DFRB as the sole source of AA. Chromic oxide (0.3%) was used as an indigestible marker. Among the 9 samples, the concentrations of ether extract (EE), crude fiber (CF), NDF, ADF, starch, Ca, and P averaged 1.33 (0.50% to 4.14%), 14.54 (9.78% to 23.85%), 28.62 (20.19% to 38.85%), 14.22 (9.32% to 23.99%), 38.80% (30.62% to 47.55%), 0.16% (0.09% to 0.24%), and 1.96% (1.11% to 2.28%), respectively. The average DE and ME were 2,643 and 2,476 kcal/kg DM, respectively, and ranged from 2,039 to 3,157 kcal/kg DM and 1,931 to 2,978 kcal/kg DM, respectively. In Exp. 2, there were significant differences in the AID and SID of CP and most AA except for His, Tyr, and Met (P < 0.05). The AID and SID of CP averaged 67.75% and 76.37%, respectively. The digestibility of Met was the greatest, averaging 86.15% and 90.08% for AID and SID, respectively. The AID and SID of Lys ranged from 51.88% to 71.43% (mean = 63.27%) and from 61.93% to 79.98% (mean = 72.97%), respectively. These results indicated that there is significant variability in chemical composition, energy content, and the SID and AID of CP and most AA among the selected DFRB. The DE and ME of DFRB are primarily related to their NDF and starch concentrations.

Net energy content of rice bran, defatted rice bran, corn gluten feed, and corn germ meal fed to growing pigs using indirect calorimetry.

The objective of this experiment was to determine the effects of increased fiber content in diets on heat production (HP) and NE:ME ratio and to determine the NE content and NE:ME ratio of full-fat rice bran (FFRB), defatted rice bran (DFRB), corn gluten feed (CGF), and corn germ meal (CGM) fed to growing barrows using indirect calorimetry (IC). Thirty growing barrows (28.5 ± 2.4 kg BW) were allotted in a completely randomized design to 5 dietary treatments that included a corn-soybean meal basal diet and 4 experimental diets with a constant ratio of corn and soybean meal (difference method) containing 30% FFRB, DFRB, CGF, and CGF. Pigs were housed in individual metabolism crates for 20 d including 14-d adaptation to the diet and 6 d to determine the HP and total collection of feces and urine in respiration chambers. Pigs were fed their respective diets at 550 kcal ME·kg BW0.60-1·d-1 on the basis of BW measured on days 0, 7, and 14. The apparent total tract digestibility (ATTD) of DM, GE, and OM were greater (P < 0.01) in pigs fed the basal diet. The ATTD of DM, GE, and OM in pigs fed the DFRB diet were lesser (P < 0.01) when compared with those fed the basal and FFRB diets. The ATTD of ether extract (EE) in pigs fed the FFRB diet was greater (P < 0.01) compared with those fed basal, DFRB, CGF, and CGM diets. The HP adjusted for the same ME intake was greater (P < 0.01) in pigs fed the DFRB, CGF, and CGM diets compared with those fed basal and FFRB diets. The NE:ME ratio in pigs fed the FFRB diet was greater (P < 0.01) when compared with those fed the DFRB, CGF, and CGM diets. The NE content of FFRB, DFRB, CGF, and CGM determined using the IC method were 2,952, 1,100, 1,747, and 2,079 kcal/kg DM, respectively. The NE content of FFRB, CGF, and CGM determined using the IC method were 3.5%, 3.8%, and 1.8% greater, respectively, than the predicted values, whereas NE content of DFRB determined using the IC method was 2.1% lower than the predicted values. In conclusion, pigs fed the fiber-rich ingredients had greater HP and lower nutrient digestibility. However, pigs fed FFRB diets containing greater fat content had a lower heat increment and, therefore, higher utilization efficiency. The NE:ME ratio ranged from 71.6% to 82.4%. The NE of FFRB, DFRB, CGF, and CGM determined using the IC method were 2,952, 1,100, 1,747, and 2,079 kcal/kg DM, respectively.

Oligosaccharides are a key factor in prediction of amino acid digestibility in soybean meal of different origins when fed to growing pigs.

OBJECTIVE: The objective of this experiment was to determine apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of crude protein (CP) and amino acid (AA) in 15 sources of soybean meal (SBM) produced from soybeans from different countries and subsequently to establish equations for predicting the AID and SID in SBM based on their chemical composition. METHODS: Eighteen barrows (57.9±6.1 kg) fitted with a simple T-cannula were allotted into three 6×6 Latin square designs. Each period comprised a 6-d adaption period followed by a 2-d collection of ileal digesta. The 15 test diets included SBM as a sole source of AA in the diet. Another nitrogen-free diet was used to measure basal endogenous losses of CP and AA. Chromic oxide (0.3%) was used as an inert marker in each diet. RESULTS: The AID of lysine in SBM from China and USA tended to be greater than in SBM from Brazil (p<0.10). The SID of valine and proline in SBM from China was greater than in SBM from Brazil (p<0.05). The SID of lysine, threonine, cysteine and glycine in SBM from China tended to be greater than in SBM from Brazil (p<0.10). From a stepwise regression analysis, a series of AID and SID prediction equations were generated. The best fit equations for lysine in SBM were: AID lysine = 1.16 sucrose-1.81 raffinose+82.10 (R2 = 0.69, p<0.01) and SID lysine = 1.14 sucrose-1.93 raffinose-0.99 ether extract (EE)+85.26 (R2 = 0.77, p<0.01). CONCLUSION: It was concluded that under the conditions of this experiment, the oligosaccharides (such as sucrose and raffinose) can be used to predict the AID and SID of AA in SBM with reasonable accuracy.