Net energy of corn, soybean meal and rapeseed meal in growing pigs

Determination and prediction of net energy of soybean meal fed to pregnant sows by indirect calorimetry

OBJECTIVE

The study was conducted to investigate the appropriate substitution level of soybean meal (SBM) for determining its net energy (NE), and establish NE prediction equation of SBM based on the determined NE values for pregnant sows.

METHODS

In Exp. 1, eighteen pregnant sows (Landrace×Yorkshire; parity, 2 to 3) with an initial body weight (BW) of 221.2±2.6 kg at mid-gestation were blocked by BW and randomly assigned into 3 groups. Three groups fed with a corn-SBM basal diet and two test diets with 15% and 30% energy-supplying components replaced by SBM, respectively. In Exp. 2, six diets were formulated including a corn-SBM basal diet and five SBM diets (based on the substitution level determined of Exp. 1) with different soybean sources and processing methods. Moreover, 12 pregnant pigs (BW = 209.0±3.0 kg; parity, 3 to 4) at mid-gestation were arranged in a 6×3 Youden square design.

RESULTS

Increasing substitution levels of SBM linearly increased (p<0.05) fecal and urinary nitrogen excretion and the ratio of urinary energy to digestible energy (DE), while linearly decreased (p<0.05) the ratio of metabolizable energy (ME) to DE and tended to linearly decrease dietary ME (p = 0.066) and NE (p = 0.074). The coefficient of variation for the NE of SBM was lower at a 15% substitution level compared to a 30% substitution level. The nutritional compositions of SBM are influenced by the soybean sources and processing methods. As dry matter basis, NE values of SBM ranged from 11.1 to 12.7 MJ/kg and the best-fitted prediction equation for NE of SBM was: NE (MJ/kg) = -91.71+5.35×gross energy (%)-0.03×neutral detergent fiber (%; R2 = 0.96).

CONCLUSION

A substitution level of 15% was more appropriate to determine NE of SBM. Furthermore, NE values of SBM can be predicted based on their chemical compositions.

Relationship between dietary fiber physicochemical properties and feedstuff fermentation characteristics and their effects on nutrient utilization, energy metabolism, and gut microbiota in growing pigs

BACKGROUND

There is a growing focus on using various plant-derived agricultural by-products to increase the benefits of pig farming, but these feedstuffs are fibrous in nature. This study investigated the relationship between dietary fiber physicochemical properties and feedstuff fermentation characteristics and their effects on nutrient utilization, energy metabolism, and gut microbiota in growing pigs.

METHODS

Thirty-six growing barrows (47.2 ± 1.5 kg) were randomly allotted to 6 dietary treatments with 2 apparent viscosity levels and 3 β-glucan-to-arabinoxylan ratios. In the experiment, nutrient utilization, energy metabolism, fecal microbial community, and production and absorption of short-chain fatty acid (SCFA) of pigs were investigated. In vitro digestion and fermentation models were used to compare the fermentation characteristics of feedstuffs and ileal digesta in the pig's hindgut.

RESULTS

The production dynamics of SCFA and dry matter corrected gas production of different feedstuffs during in vitro fermentation were different and closely related to the physical properties and chemical structure of the fiber. In animal experiments, increasing the dietary apparent viscosity and the β-glucan-to-arabinoxylan ratios both increased the apparent ileal digestibility (AID), apparent total tract digestibility (ATTD), and hindgut digestibility of fiber components while decreasing the AID and ATTD of dry matter and organic matter (P < 0.05). In addition, increasing dietary apparent viscosity and β-glucan-to-arabinoxylan ratios both increased gas exchange, heat production, and protein oxidation, and decreased energy deposition (P < 0.05). The dietary apparent viscosity and β-glucan-to-arabinoxylan ratios had linear interaction effects on the digestible energy, metabolizable energy, retained energy (RE), and net energy (NE) of the diets (P < 0.05). At the same time, the increase of dietary apparent viscosity and β-glucan-to-arabinoxylan ratios both increased SCFA production and absorption (P < 0.05). Increasing the dietary apparent viscosity and β-glucan-to-arabinoxylan ratios increased the diversity and abundance of bacteria (P < 0.05) and the relative abundance of beneficial bacteria. Furthermore, increasing the dietary β-glucan-to-arabinoxylan ratios led to a linear increase in SCFA production during the in vitro fermentation of ileal digesta (P < 0.001). Finally, the prediction equations for RE and NE were established.

CONCLUSION

Dietary fiber physicochemical properties alter dietary fermentation patterns and regulate nutrient utilization, energy metabolism, and pig gut microbiota composition and metabolites.

Poultry Nutrition: Achievement, Challenge, and Strategy

Poultry, a vital economic animal, provide a high-quality protein source for human nutrition. Over the past decade, the poultry industry has witnessed substantial achievements in breeding, precision feeding, and welfare farming. However, there are still many challenges restricting the sustainable development of the poultry industry. First, overly focused breeding strategies on production performance have been shown to induce metabolic diseases in poultry. Second, a lack of robust methods for assessing the nutritional requirements poses a challenge to the practical implementation of precision feeding. Third, antibiotic alternatives and feed safety management remain pressing concerns within the poultry industry. Lastly, environmental pollution and inadequate welfare management in farming have a negative effect on poultry health. Despite numerous proposed strategies and innovative approaches, each faces its own set of strengths and limitations. In this review, we aim to provide a comprehensive understanding of the poultry industry over the past decade, by examining its achievements, challenges, and strategies, to guide its future direction.

Effect of Dietary Sugarcane Bagasse on Reproductive Performance, Constipation, and Gut Microbiota of Gestational Sows

This experiment aimed to evaluate the effects of using sugarcane bagasse (SB) as a substitute for soybean hulls and wheat bran in the diet of pregnant sows on their reproductive performance and gut microbiota. A total of seventy-two primiparous sows were randomly divided into four treatment groups, with eighteen replicates of one sow each. The sows were fed a basal diet supplemented with 0% (CON), 5%, 10%, and 15% SB to replace soybean hulls from day 57 of gestation until the day of the end of the gestation period. The results showed that SB contains higher levels of crude fiber (42.1%) and neutral detergent fiber (81.3%) than soybean hulls, and it also exhibited the highest volumetric expansion when soaked in water (50 g expanding to 389.8 mL) compared to the other six materials we tested (vegetable scraps, soybean hulls, wheat bran, rice bran meal, rice bran, and corn DDGS). Compared with the CON, 5% SB significantly increased the litter birth weight of piglets. Meanwhile, 10% and 15% SB significantly increased the rates of constipation and reduced the contents of isobutyric acid and isovaleric acid in feces. Furthermore, 10% and 15% SB significantly disturbed gut microbial diversity with increasing Streptococcus and decreasing Prevotellaceae_NK3B31-group and Christensenellaceae_R-7-group genera in feces. Interestingly, Streptococcus had a significant negative correlation with isobutyric acid, isovaleric acid, and fecal score, while Prevotellaceae_NK3B31-group and Christensenellaceae_R-7-group had a positive correlation with them. In conclusion, our study indicates that 5% SB can be used as an equivalent substitute for soybean hulls to improve the reproductive performance of sows without affecting their gut microbiota.

Determination and prediction of the net energy content of wheat bran for pregnant sow

Two experiments were conducted to determine net energy (NE) values of wheat bran ingredients and develop a prediction equation for NE of wheat bran. In each experiment, 12 multiparous pregnant sows were allocated to two 3 × 6 Youden squares with three consecutive periods and six diets in each square. The study consisted of six diets, including a corn-soybean meal basal diet and five diets formulated with 29.2% wheat bran. Each period lasted for 10 d, with 5 d allocated for adaptation and followed by 5 d for heat production measurement. Sows were provided feed at 604 kJ/kg BW0.75·d-1. On day 10, sows underwent fasting to measure fasting heat production. Results indicated that the inclusion of wheat bran in the diets significantly reduced digestibility of energy and nutrients in (p < 0.05). The average net energy (NE) content of wheat bran was determined to be 8.8 MJ/kg DM. A regress equation NE = 7.968 + 0.28 × CP + 0.607 × EE - 0.782 × ash - 0.05 × hemicellulose (R2 = 0.98, p < 0.01) was found to accurately predit the NE value when feeding pregnant sows with wheat bran-based diets. In conclusion, the net energy content of wheat bran fed to pregnant sows ranged from 7.24 to 10.67 MJ/kg DM and can be effectively estimated using proximate analysis methods.

Evaluation of Effective Energy Values of Six Protein Ingredients Fed to Beagles and Predictive Energy Equations for Protein Feedstuff

This study evaluated the nutrition composition, the nutrient digestibility, and the energy value of six protein ingredients used in pet food by the difference method in six beagles within a 7 × 6 incomplete Latin square design. The results showed that the apparent total tract digestibility of gross energy (GE) and organic matter (OM) in beagles fed the fish meal (FM) and corn gluten meal (CGM) diets was higher than for those fed the meat and bone meal (MBM), soybean meal (SBM), mealworm meal (MM), and yeast extract (YE) diets (p < 0.05). The digestible energy (DE), metabolizable energy (ME), and net energy (NE) of the MM diet were greater than the other diets, and MBM was the lowest (p < 0.05). The ME of protein ingredients was positively correlated with organic matter and negatively correlated with the ash content. The NE of protein ingredients was positively correlated with the crude protein content and negatively correlated with the ash content. The study resulted in predictive energy equations for protein ingredients that were more accurate than the NRC's predictive equation of ME when the ash content of the ingredient was more than 30% DM. In conclusion, the nutrient digestibility and energy value of corn gluten meal were similar to those of fish meal and those of soybean meal were similar to yeast extract. All predictive energy equations for six protein feedstuffs had slight differences with measured energy values.

Different fat-to-fiber ratios by changing wheat inclusion level impact energy metabolism and microbial structure of broilers

Introduction

Dietary nutrient content is crucial for energy metabolism and development of gut microbiota. Herein, this study aimed to explore the effects of fat-to-fiber ratios on nutrient transporter, energy metabolism and gut microbiota when ingredients composition was altered.

Methods

A total of 240 as-hatched broiler chickens were randomly assigned into three groups including low fat-high dietary fiber (LF-HD), medium fat-medium dietary fiber (MF-MD) and high fat-low dietary fiber (HF-LD), with diets being iso-protein, and broilers were offered the same commercial diets from 21 to 42 d. The data were analyzed using one-way ANOVA of SPSS.

Results and Discussion

Results showed that HF-LD diet significantly increased glucose content and decreased triglyceride in serum of broilers (p < 0.05). The mRNA abundance of jejunal gene involved in glucose transporter and tricarboxylic acid (TCA) cycle was significantly increased in broilers fed with HF-LD diets. Compared with LF-HD, HF-LD had a lower abundance of Anaerofilum and CHKCI001, and an increased proportion of beneficial bacteria such as Alistipes, Catenibacillus, Intestinimonas, Lactobacillus, and Peptococcus (p < 0.05). Functional prediction of these microbial changes indicated that HF-LD diet drove caecal microbiota to participate in carbohydrate metabolism and TCA cycle (p < 0.05). Dietary HF-LD-induced microbiota changes were positively correlated with growth performance of broilers (p < 0.05). Therefore, HF-LD diet increased glucose transporters and energy metabolism in intestine and shaped microbial structure and metabolic pathways, which may benefit the growth performance of broilers.

Wheat bran inclusion level impacts its net energy by shaping gut microbiota and regulating heat production in gestating sows

An accurate estimation of net energy (NE) of wheat bran is essential for precision feeding of sows. However, the effects of inclusion level on NE of wheat bran have not been reported. Inclusion level was hypothesized to impact NE of wheat bran by regulating gut microbiota and partitioning of heat production. Therefore, twelve multiparous sows (Yorkshire × Landrace; 2 to 4 parity) were assigned to a replicated 3 × 6 Youden square with 3 successive periods and 6 diets in each square. The experiment included a corn-soybean meal diet (WB0) and five diets including 9.8% (WB10), 19.5% (WB20), 29.2% (WB30), 39.0% (WB40) and 48.7% wheat bran (WB50), respectively. Each period included 6 d of adaptation to diets followed by 6 d for heat production measurement using open-circuit respiration chambers. Compared with other groups, WB30, WB40, and WB50 enriched different fiber-degrading bacteria genera (P < 0.05). Apparent total tract digestibility of neutral detergent fiber and acid detergent fiber of wheat bran were greater in WB30 and WB40 (P < 0.05). Physical activity (standing and sitting) decreased as inclusion level increased (P = 0.04), which tended to decrease related heat production (P = 0.07). Thermic effect of feeding (TEF) was higher in WB50 than other treatments (P < 0.01). Metabolizable energy of wheat bran was similar among treatment groups (except for WB10). NE of wheat bran conformed to a quadratic regression equation with inclusion level (R2 = 0.99, P < 0.01) and peaked at an inclusion level of 35.3%. In conclusion, increasing inclusion level decreased energy expenditure of sows on physical activity and promoted growth of fiber-degrading bacteria, which improved energy utilization of fiber. Fermentation of wheat bran fiber by Prevotellaceae_UCG-003 and norank_f__Paludibacteraceae might increase TEF. Consequently, sows utilized energy in wheat bran most efficiently at an inclusion level of 35.3%.

Modeling net energy partition patterns of growing-finishing pigs using nonlinear regression and artificial neural networks

The objectives of this study were to evaluate the net energy (NE) partition patterns of growing-finishing pigs at different growing stages and to develop the corresponding prediction models using nonlinear regression (NLR) and artificial neural networks (ANN). Twenty-four pigs with an initial body weight (BW) of ~30 kg were kept in metabolic cages and fed ad libitum and were moved into six respiration chambers in turns until ~90 kg. The NE partition patterns, i.e., NE for maintenance (NEm), NE retained as protein (NEp), and NE retained as lipid (NEl), were calculated based on indirect calorimetry and nitrogen balance techniques. The energy balance data collected through the animal trial was then randomly split into a training data set containing 75% of the samples and a testing data set containing the remaining 25% of the samples. The NLR models and a series of ANN models were established on the training data set to predict the metabolizable energy intake, NE intake, NEm, NEp, and NEl of pigs. The best-fitted ANN models were selected by 5-fold cross-validation in the training data set. The prediction performance of the best-fitted NLR and ANN models were compared on the testing data set. The results showed that the average NE intakes of pigs were 17.71, 23.25, 24.56, and 28.96 MJ/d in 30 to 45 kg, 45 to 60 kg, 60 to 75 kg, and 75 to 90 kg, respectively. The NEm and NEl (MJ/d) kept increasing as BW increased from 30 kg to 90 kg, while the NEp increased to its maximum value and then kept in a certain range of 4.64 to 4.88 MJ/d. The proportion of NEm for pigs at 30 to 90 kg stayed within the range of 42.0% to 48.6%, while the proportion of NEl kept increasing. For the prediction models built based on the animal trial, ANN models exhibited better performance than NLR models for all the target outputs. In conclusion, NE partition patterns changed in different growth stages of pigs, and ANN models are more flexible and powerful than NLR models in predicting the NE partition patterns of growing-finishing pigs.

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.

Methodologies for energy evaluation of pig and poultry feeds: A review

The cost of feed represents an important part of the total cost in swine and poultry production (>60%) with energy accounting for at least 70% of feed cost. The energy value of ingredients or compound feeds can be estimated as digestible (DE), metabolisable (ME) and net energy (NE) in pigs and ME and NE in poultry. The current paper reviews the different methods for evaluating DE, ME and NE of feeds for monogastric animals and their difficulties and limits, with a focus on NE. In pigs and poultry, energy digestibility depends on the chemical characteristics of the feed, but also on technology (pelleting, for instance) and animal factors such as their health and body weight. The ME value includes the energy losses in urine that are directly dependent on the proportion of dietary N excreted in urine resulting in the concept of ME adjusted for a zero N balance (MEn) in poultry. For poultry, the concept of true ME (TME, TMEn), which excludes the endogenous fecal and urinary energy losses from the excreta energy, was also developed. The measurement of dietary NE is more complex, and NE values of a given feed depend on the animal and environmental factors and also measurement and calculation methods. The combination of NE values of diets obtained under standardised conditions allows calculating NE prediction equations that are applicable to both ingredients and compound feeds. The abundance of energy concepts, especially for poultry, and the numerous feed and animal factors of variation related to energy digestibility or ME utilisation for NE suggest that attention must be paid to the experimental conditions for evaluating DE, ME or NE content. This also suggests the necessity of standardisations, one of them being, as implemented in pigs, an adjustment of ME values in poultry for an N retention representative of modern production conditions (MEs). In conclusion, this review illustrates that, in addition to numerous technical difficulties for evaluating energy in pigs and poultry, the absolute energy values depend on feed and animal factors, the environment, and the methods and concepts. Finally, as implemented in pigs, the use of NE values should be the objective of a more reliable energy system for poultry feeds.

Age-dependent development in protein digestibility and intestinal morphology in weaned pigs fed different protein sources

Today, weaner diets are optimised using digestibility coefficients obtained from grower-finisher pigs, which may overestimate the digestibility in weaners. The aim of this study was to evaluate the standardised ileal digestibility (SID) of CP and amino acids (AAs), and the intestinal morphology in pigs 0-4 weeks postweaning when fed different protein sources. The experiment included 128 pigs weaned at day 28 and the protein sources were wheat, soybean meal (SBM), enzyme-treated soybean meal (ESBM), hydrothermally treated rapeseed meal (HRSM) and casein. The experiment was conducted as a difference method study including wheat in all diets. Eight pigs were slaughtered on the day of weaning (day 0) and six pigs/treatment were slaughtered at days 7, 14, 21, and 28 postweaning. The SID of CP and AA, as average over the four weeks, was lowest for ESBM and highest for wheat and casein, with SBM and HRSM being intermediate. The SID of CP and AA increased (both linear and quadratic, P < 0.05) over time after weaning. The average SID of CP for all protein sources postweaning was 0.38, 0.59, 0.76, and 0.71 on days 7, 14, 21, and 28, respectively. These differences were significant (P < 0.05) between days 7 and 21, and between days 7 and 28 (P < 0.05), whereas there tended to be a difference between days 7 and 14 (P = 0.06). Protein source did not affect the small intestinal morphology response parameters, whereas time after weaning did. Villous height and villous height to crypt depth ratio differed (P < 0.05) between the days 0 and 7, with shorter villi and a higher ratio at day 7. Crypt depth was not altered between days 0 and 7, or between days 7 and 14. For villi density, crypt density and small intestinal length, a significant increase from days 7 to 14 was observed, but there was no further increase to or difference between days 21 and 28. In conclusion, the low SID of CP in casein on day 7 (0.50) illustrates the challenges related to protein digestion in weanling pigs. The SID of CP and AA is very low during the first two weeks postweaning and time after weaning is more important for protein digestibility, than the source of protein. Fewer mature epithelial cells and less absorptive area in the small intestine in the early postweaning period may partly explain the poor protein digestibility.

Effects of Supplementing Intestinal Autochthonous Bacteria in Plant-Based Diets on Growth, Nutrient Digestibility, and Gut Health of Bullfrogs (Lithobates catesbeianus)

Poor utilization efficiency of plant protein diets always leads to intestinal barrier dysfunction and growth inhibition in animals. Probiotics have shown promise in improving growth performance and gut health of the host. However, obtaining the host-beneficial probiotic from thousands of bacterial phylotypes is challenging. Here, four intestinal autochthonous bacteria were isolated from fast-growing bullfrog after a 60-day feeding on a soybean meal (SM)-based diet. Another feeding trial was conducted to evaluate the effects of supplementing these strains in an SM-based diet on growth, nutrient digestibility, immunity, and gut health of bullfrog. A high-SM basal diet was used as a non-supplemented control group (NC), and four other diets were prepared by supplementing the basal diet with 1 × 10⁷ CFU/g of Bacillus siamensis, Bacillus tequilensis (BT), Bacillus velezensis, and Lactococcus lactis (LL). Results showed that weight gain, feed efficiency, nitrogen retention, and apparent digestibility coefficients of dry matter and protein were significantly higher in the LL group compared with the NC group (p < 0.05). Furthermore, compared with the NC group, both BT and LL groups showed markedly higher jejunal protease and amylase activities, serum complement 4 and immunoglobulin M levels, jejunal muscularis thickness (p < 0.05), and up-regulated expression of il-10 and zo-1 genes (p < 0.05). High-throughput sequencing revealed higher abundances of Bacillus and Cetobacterium in BT and LL groups, respectively, accompanied with decreased abundances of Enterobacter and Escherichia-Shigella. Besides, KEGG pathways related to metabolisms were significantly enhanced by the LL diet relative to the NC diet (p < 0.05). Overall, the beneficial effects of two frog-derived probiotics were determined: supplementation of L. lactis in SM-based diet promoted growth and nutrient digestibility; both B. tequilensis and L. lactis supplementation improved immune response and intestinal barrier function of bullfrogs.

Effects of increasing standardized ileal digestible lysine during gestation on reproductive performance of gilts and sows

Limited information is available on lysine requirement estimates of modern, high-producing gestating sows Therefore, the objective of this study was to evaluate the effects of increasing standardized ileal digestible (SID) lysine during gestation on piglet birthweight and reproductive performance of gilts and sows. A total of 936 females (498 gilts, 438 sows; Camborough®, PIC, Hendersonville, TN) were group-housed (approximately 275 females per pen) and individually fed with electronic sow feeders. Females were moved from the breeding stall to pens on d 4 of gestation and allotted to one of four dietary treatments on d 5. Dietary treatments included increasing SID lysine intake (11.0, 13.5, 16.0, and 18.5 g/d). Gilts (parity 1) and sows (parity 2+) received 2.1 and 2.3 kg (22.2 and 24.3 MJ net energy per day) of feed throughout the entire gestation period, respectively. Dietary treatments were achieved by different blends of low (0.48% SID lysine) and high (0.88% SID lysine) lysine diets, prepared by changing the amount of corn and soybean meal in these two diets. Female weight and backfat were recorded on d 4 and 111 of gestation. Individual piglet weight was obtained within 12 h of birth on litters from 895 females. Final weight, and calculated maternal BW, body lipid, and body lean at d 111 of gestation increased (linear, P < 0.01) for gilts and sows as SID lysine increased. There was no evidence for differences in final backfat depth. Average total born for gilts and sows was 15.3 and 16.0 pigs with no evidence for differences among treatments. The percentage of pigs born alive increased (P = 0.01) with increasing SID lysine intake for sows, but not in gilts as a result of a treatment by parity group interaction (P = 0.04) for percentage of stillborn pigs. Increasing SID lysine intake during gestation did not affect the percentage of mummified fetuses, total born, or birthweight of piglets born alive in this study. In addition, increasing SID lysine intake during gestation did not affect subsequent reproductive performance. In conclusion, increasing dietary SID lysine intake in gestation increased female BW, without changing backfat depth. The minimal effects on female reproductive performance and piglet birthweight suggest that 11 g/day of SID lysine intake appears to be adequate for gestating gilts and sows; however, providing sows with 18.5 g/d SID lysine reduced (P = 0.01) stillbirth rate by 2.3 percentage points.

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

Simple Summary

In recent years, prices of imported staples such as corn and soybean meal have risen dramatically. Defatted rice bran (DFRB), an abundant and underutilized agricultural coproduct of the paddy rice, was a replacement of corn and soybean meal. It is necessary to comprehensively evaluate the nutritional value of DFRB. This study determined and compared the net energy (NE) of DFRB from different sources and different processing technology fed to growing pigs using indirect calorimetry. Results indicated that NE contents of extruded DFRB from different provinces were within the range of values ((8.24 to 10.22 MJ/kg dry matter (DM)). The NE contents of extruded DFRB and pelleted DFRB from the same province were 8.24 vs. 6.56 MJ/kg DM. This study showed that there is a discrepancy of approximately 10.01% in the NE content between the DFRB origins. The data above suggested that NE content of DFRB could be related to DFRB origins and processing technology. More NE contents of different DFRB samples deserve to be explored further. The study supported some theoretical foundation for the application of DFRB in the NE system.

Abstract

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 BW^0.6/day and 746 vs. 726 kJ/kg BW^0.6/day respectively, and those in extruded DFRB from different origins were within the range of values (947 to 1105 kJ/kg BW^0.6/day and 726 to 755 kJ/kg BW^0.6/day, respectively). In conclusion, NE values are affected by origin and processing technology of DFRB.

Concerns about the misleading conclusions regarding estimation of the net energy value of soybean meal relative to corn using the caloric efficiency approach in pigs

Apart from energy balance trials such as calorimetry, growth trials could also be used to estimate the energy values of feed ingredients with caloric efficiency as an indicator. Recent work used such methods reported greater net energy (NE) value of soybean meal (SBM) relative to corn in nursery pigs. We theoretically compared the NE values of SBM and corn according to the definition of NE and properties of the major chemical compositions in each ingredient. Meanwhile, we thoroughly examined the diet formulations and related analysis used in this work and compared this study with some peer works. We found that this study may suffer from problems with experimental design, reference citation, and data interpretation. In summary, the conclusion from the recent work that the SBM NE value may be greater than the corn NE value is likely to be erroneous.

Progress towards pig nutrition in the last 27 years

Over the last 27 years (1990-2017), based on the revolutionary progresses of basic nutrition research, novel methods and techniques have been developed which bring a profound technological revolution to pig production from free-range system to intensive farming all over the world. Basic theoretical innovations and feed production studies have provided vital advancements in pig nutrition by developing formula feed, utilizing balanced diets, determining feed energy value, dividing pig physiological stages, enhancing gut health, and improving feed processing technique. Formula feed is the primary contributor of the rise of the mechanized farming industry, and meets comprehensive nutritional needs of the pig. The focuses of the development of a balanced diet by optimizing nutrient levels are the amino acids balance, the balance between amino acids and energy, the balance between calcium and phosphorus. Multiple-site-production and targeted feeding program have been applied extensively. Early weaning of piglets improves production efficiency, but piglets that have not yet fully developed their intestine are prone to diarrhea. Therefore, intestinal health has received special attention in recent years. Feed processing technologies, such as granulation, puffing, fermentation and enzymatic hydrolysis, can improve the utilization of feed nutrients and reduce production cost. However, increasing a sow's potential for production, seeking alternatives to antibiotics, reducing drug treatment in piglets, developing functional additives and improving meat quality remain future challenges. Herein, we outline the important progresses of pig nutrition in the past 27 years, which will shed light on the basic nutrition rules of pig production, and help to push forward its future development. © 2018 Society of Chemical Industry.

Effects of dietary crude protein level and N-carbamylglutamate supplementation on nutrient digestibility and digestive enzyme activity of jejunum in growing pigs

Three experiments were conducted to investigate the effects of dietary crude protein (CP) level and N-carbamylglutamate (NCG) supplementation on apparent total tract digestibility (ATTD) and ileal digestibility of nutrients and digestive enzyme activity of jejunum in growing pigs. In experiment 1, 10 Duroc × Landrace × Yorkshire barrows (initial BW: 48.7 kg) were allotted to a three-period switchback design with five experimental diets and two replicate pigs per diet in each period. Diets were categorized as high CP (HP, 18% CP), moderate low CP (MLP, 15% CP), very low CP (VLP, 12% CP), and MLP and VLP with 0.1% NCG supplementation. Feces and urine were collected from day 6 to day 11 after a 5-d adaptation period. The DE, ME, and ATTD of GE, OM, CP, NDF, ADF, and P decreased (P < 0.01) with a reduction of dietary CP, but no effect of dietary treatments on pig daily N retention was detected. The NCG supplementation increased (P < 0.01) DE and ATTD of ADF of the VLP diet. In experiment 2, 10 jejunal-cannulated Duroc × Landrace × Yorkshire barrows (initial BW: 44.5 kg) were fed five diets for three periods as experiment 1. Jejunal fluid was collected on days 6 and 8 after a 5-d adaptation period. The digestive enzymes activity was not affected by dietary CP level, except for α-amylase, for which there was a decrease (P < 0.01) in pigs fed VLP diets compared to HP and MLP diets. In experiment 3, 12 ileal-cannulated Duroc × Landrace × Yorkshire barrows (initial BW: 46.7 kg) were allotted to a three-period switchback design with six diets and two replicate pigs per diet in each period. The six experimental diets consisted of five experimental diets as experiment 1 and one N-free diet. Ileal digesta was collected from day 6 to day 8 after a 5-d adaptation period. Results indicated that apparent ileal digestibility (AID) of CP and P and ileal digestibility of Arg, His, Ile, Leu, Phe, and all dispensable AA, except Pro, decreased (P < 0.01) in pigs fed VLP diet compared to HP and MLP diets, but AID of GE, OM, EE, NDF, and ADF were not affected. The supplementation of NCG in the VLP diet increased (P < 0.01) the AID of CP and ileal digestibility of Arg, His, Leu, Phe, Val, Ser, and Tyr. In conclusion, reducing dietary CP level decreased nutrient digestibility, but improved the efficiency of dietary N utilization and reduced N emission. Moderate reduction of dietary CP level had a minimal effect on nutrient digestibility and digestive enzyme activity. Additionally, NCG supplementation plays a beneficial effect on nutrient digestion only if the dietary CP level is extremely lowered.

Effect of dietary near ideal amino acid profile on heat production of lactating sows exposed to thermal neutral and heat stress conditions

BACKGROUND

Reduced protein diet manifested potential to mitigate heat production based on the concept of ideal amino acid profile. The hypothesis of this study was that lactating sows fed a low crude protein (LCP) diet with supplemental amino acid produce less heat compared to those fed a high crude protein (HCP) diet under both thermal neutral (TN) and heat stress (HS) conditions.

METHODS

Thirty-two lactating sows were allotted to HCP (193 g CP/kg) and LCP (140 g CP/kg) diets under thermal neutral (TN, 21 ± 1.5 °C) or cycling heat stress (HS, 32 ± 1.5 °C daytime and 24 ± 1.5 °C nighttime) conditions. Diets contained 0.90% SID lysine and 10.8 MJ/kg net energy. Positive pressure indirect calorimeters were used to measure gas exchange in individual sows with litters, and individual piglets on days 4, 8, 14 and 18. Sow and litter weights were recorded on days 1, 10 and 21.

RESULTS

Sow total heat production (THP) was calculated by subtracting litter THP from sow + litter THP based on BW0.75. Sow BW and body protein (BP) loss was greater for LCP diet compared to HCP diet in peak lactation (P < 0.05 and P < 0.01, respectively) and throughout the entire lactation period (P < 0.05 and P = 0.056, respectively) under HS conditions. Heat-stressed sows fed HCP diet had higher (P < 0.05) rectal temperature at 13:00 (P < 0.05) and 19:00 (P < 0.01), and higher respiration rate at 07:00 (P <  0.05), 13:00 (P < 0.05) and 19:00 (P < 0.05) compared to TN sows fed HCP diet. In sows fed LCP diet, those under HS tended to have higher (P = 0.098) rectal temperature at 13:00 and had higher (P <  0.05) respiration rate at 07:00, 13:00 and 19:00 compared to TN sows. The relationship between daily THP and days in lactation of sows fed LCP diet was quadratic (P < 0.05), with an ascending trend until day 14 and a descending trend from days 14 to 18. Sows fed LCP diet had lower daily THP at day 18 (P < 0.001) compared to those fed the HCP diet under HS conditions.

CONCLUSION

Reduction in THP in sows fed LCP diet was largely associated with THP on day 18 of lactation under HS conditions. Feeding LCP diets alleviated the increased body temperature in sows under HS conditions throughout lactation, which was accompanied by a reduction in respiration rate. Total heat production is associated with days in lactation, in particular under HS conditions with THP appearing to peak between days 14 and 18.

Estimate of the energy value of soybean meal relative to corn based on growth performance of nursery pigs

Background

Two experiments were conducted to determine the effects of increasing amounts of soybean meal (SBM) in swine diets and estimate the energy value of SBM.

Methods

A total of 2233 pigs (PIC 337 × 1050, Hendersonville, TN) and 3796 pigs (PIC 359 × C40), initially 11.0 kg and 17.6 kg body weight (BW), were used in Exp. 1 and 2, respectively. In Exp. 1, pigs were placed in 92 pens each containing 20 to 27 pigs. In Exp. 2, pigs were placed in 84 pens each containing 37 to 43 pigs. Treatments were assigned in a randomized complete block design with BW as the blocking factor. Dietary treatments consisted of 21%, 27%, 33%, or 39% SBM in Exp. 1 and 17.5%, 22%, 26.5%, 31%, 35.5%, or 40% SBM in Exp. 2, obtained by changing the inclusion rate of feed-grade amino acids and corn grain. For Exp. 1, representative samples of corn grain, SBM, and distillers dried grains with solubles were analyzed for total AA content prior to diet formulation. For Exp. 2, diets were formulated using NRC (2012) nutrient loadings. Treatment diets were fed for 21 and 22 d (Exp. 1 and 2) and there were 23 replicates in Exp. 1 and 14 replicates in Exp. 2. Pigs were weighed and feed disappearance measured weekly to calculate average daily gain (ADG), average daily feed intake (ADFI), gain-to-feed ratio (G:F), and caloric efficiency (CE). Data were analyzed with block as a random effect and treatment as a fixed effect, and contrasts were constructed to test the linear and quadratic effects of increasing SBM.

Results

In Exp. 1, there was a tendency (linear, P = 0.092) for a decrease in ADFI as SBM increased. There was a tendency (P = 0.090) for a quadratic response for ADG, with a decrease in ADG observed with 39% SBM inclusion. Pigs fed diets with increasing SBM had a tendency (quadratic, P = 0.069) for an increase in G:F up to 33% SBM and an improvement (linear, P = 0.001; quadratic, P = 0.063) in CE with increasing SBM. Using CE to estimate the energy of SBM relative to corn, a value of 105.4% of corn energy or 2816 kcal/kg NE was determined using all data points. When removing the CE value of the 39% SBM treatment due to the quadratic tendency, SBM was estimated to have 121.1% of corn energy or 3236 kcal/kg NE. In Exp. 2, there was a decrease (linear, P = 0.001) in ADFI. Pigs fed increasing SBM had a tendency (linear, P = 0.065) for reduced ADG but an improvement (linear, P = 0.001) in G:F and CE as SBM increased. The energy value of SBM was estimated as 124.7% of corn energy or 3332 kcal/kg NE.

Conclusions

The results suggest that feeding increasing levels of SBM improves G:F and CE. The energy value of SBM was estimated to be between 105% and 125% of corn, which is much greater than the NRC (2012) would indicate.

Effects of soybean meal level on growth performance of 11- to 25-kg nursery pigs

Four experiments were conducted to determine the effects of increasing soybean meal (SBM) level in diets with or without 25% distillers dried grains with solubles (DDGS) on growth performance of nursery pigs raised in university or commercial facilities. Treatments were arranged in a 2 × 3 factorial with main effects of SBM (27.5%, 32.5%, or 37.5% of the diet) and DDGS (0% or 25% of the diet). A total of 296, 2,502, 4,118, and 711 pigs with initial body weight (BW) of 10.6, 11.7, 12.5, and 12.3 kg were used in Exp. 1, 2, 3, and 4, respectively. There were 10, 16, 13, and 12 replicates per treatment in Exp. 1, 2, 3, and 4, respectively. After weaning, pigs were fed common diets for approximately 21 d. Then, pens of pigs were assigned to treatments in a randomized complete block design with BW as the blocking factor and experimental diets were fed for 21 d. Pigs were weighed and feed disappearance measured to calculate average daily gain (ADG), average daily feed intake (ADFI), gain-to-feed ratio (G:F), and caloric efficiency (CE). Data were analyzed using the GLIMMIX procedure of SAS with block as a random effect and treatment as a fixed effect. Single degree-of-freedom contrasts were constructed to test the linear and quadratic effects of increasing SBM and their interactions with DDGS. Pigs used in all experiments did not undergo major health challenges during the experimental period and due to the low number of mortality and cull events, statistical analysis was not performed on these variables. The average cull rate was 0.7%, 0.5%, 0.2%, and 0%, and the mortality rate was 0.7%, 0.3%, 0.4%, and 0% in Exp. 1–4, respectively. There were interactions (P ≤ 0.039) between SBM and DDGS for G:F and CE in Exp. 2 and for ADG and ADFI in Exp. 3. These were mostly driven by increasing SBM negatively affecting performance in a greater magnitude when diets contained DDGS compared to diets without DDGS. The main effects of DDGS and SBM were more consistently observed across experiments. Pigs fed diets with 25% DDGS had decreased (P ≤ 0.001) ADG and ADFI in all experiments, as well as poorer (P ≤ 0.028) G:F and CE except for Exp. 3. Feeding increasing amounts of SBM generally did not result in any major impact in ADG but consistently improved (linear, P ≤ 0.078) G:F and CE across experiments.

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 BW^0.6/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 BW^0.6/d and fasted on day 16 for evaluation of fasting heat production (FHP).

Results

The FHP of pigs averaged 790 kJ/kg BW^0.6/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.

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.

Dietary protein reduction improves the energetic and amino acid efficiency in lactating sows

Strategies to mitigate the environmental impact of swine production are essential to contribute to the sustainability of the swine industry. Our work has focussed on the area of dietary crude-protein (CP) reduction with crystalline amino acid (CAA) supplementation to create diets containing a near ‘ideal’ amino acid (AA) balance, and to assess the environmental impact of feeding these diets to lactating sows. Additionally, with an increasing availability of CAA at competitive costs relative to feed-ingredient proteins, precise prediction of requirements of the less traditionally limiting AA such as histidine, isoleucine, leucine, phenylalanine and valine are ever more relevant. Prediction of AA requirements using modelling approaches is dependent on accurate estimates of AA efficiency of utilisation for milk-protein production. Aggressive reduction in dietary CP and CAA supplementation to improve dietary AA balance minimises urea-nitrogen (N) synthesis, N excretion and ammonia emission, without compromising lactation performance. Improving dietary AA balance increases energy, global N and AA efficiency of utilisation for milk production, and, in some cases, increases true milk protein and casein yield in peak lactation. The mechanisms by which enhanced AA balance improves nutrient efficiency include potentially increased extraction rate of AA by the mammary gland and reduced heat production. Individual AA efficiencies are dynamic, and, thus, estimating their maximum biological efficiency value (MBEV) is of critical importance for accurate prediction of AA requirements. We have estimated MBEV for each individual AA. Future dietary formulations using reduced CP diets to minimise N excretion and ammonia emission will require AA requirements based on MBEV estimates.

Net energy content of rice bran, corn germ meal, corn gluten feed, peanut meal, and sunflower meal in growing pigs

OBJECTIVE

The objective of this experiment was to determine the net energy (NE) content of full-fat rice bran (FFRB), corn germ meal (CGM), corn gluten feed (CGF), solvent-extracted peanut meal (PNM), and dehulled sunflower meal (SFM) fed to growing pigs using indirect calorimetry or published prediction equations.

METHODS

Twelve growing barrows with an average initial body weight (BW) of 32.4±3.3 kg were allotted to a replicated 3×6 Youden square design with 3 successive periods and 6 diets. During each period, pigs were individually housed in metabolism crates for 16 d, which included 7 days for adaptation. On d 8, the pigs were transferred to the respiration chambers and fed one of the 6 diets at 2.0 MJ metabolizable energy (ME)/kg BW0.6/d. Total feces and urine were collected and daily heat production was measured from d 9 to d 13. On d 14 and d15, pigs were fed at their maintenance energy requirement level. On the last day pigs were fasted and fasting heat production was measured.

RESULTS

The NE of FFRB, CGM, CGF, PNM, and SFM measured by indirect calorimetry method was 12.33, 8.75, 7.51, 10.79, and 6.49 MJ/kg dry matter (DM), respectively. The NE/ME ratios ranged from 67.2% (SFM) to 78.5% (CGF). The NE values for the 5 ingredients calculated according to the prediction equations were 12.22, 8.55, 6.79, 10.51, and 6.17 MJ/kg DM, respectively.

CONCLUSION

The NE values were the highest for FFRB and PNM and the lowest in the corn co-products and SFM. The average NE of the 5 ingredients measured by indirect calorimetry method in the current study was greater than values predicted from NE prediction equations (0.32 MJ/kg DM).

Determination of net energy content of dietary lipids fed to growing pigs using indirect calorimetry

The objective of this experiment was to determine the NE content of different dietary lipids fed to growing pigs using indirect calorimetry. Thirty-six growing (initial BW: 41.1 ± 3.1 kg) barrows were allotted to 6 diets based on completely randomized design with 6 replicate pigs per diet. Diets included a corn-soybean meal basal diet and 5 test diets each containing 10% palm oil, poultry fat, fish oil, corn oil, or flaxseed oil at the expense of corn and soybean meal. During each period, pigs were individually housed in metabolism crates for 14 d, which included 7 d for adaptation to feed, metabolism crates, and environmental conditions. On day 8, pigs were transferred to the open-circuit respiration chambers and fed 1 of the 6 diets at 2.3 MJ ME/kg BW0.6/day. Total feces and urine were collected and daily heat production (HP) was also calculated from day 9 to day 13. On the last day of each period (day 14), pigs were fasted and the fasting heat production (FHP) was measured. The results show that the FHP of pigs averaged 809 kJ/kg BW0.6·day-1 and was not affected by diet characteristics. The DE values were 35.98, 36.84, 37.11, 38.95, and 38.38 MJ/kg DM, the ME values were 35.79, 36.56, 36.92, 37.73, and 38.11 MJ/kg DM, and the NE values were 32.42, 33.21, 33.77, 34.00, and 34.12 MJ/kg DM, for the palm oil, poultry fat, fish oil, corn oil, and flaxseed oil, respectively. Based on our result, we concluded that the DE content of dietary lipid varied from 91% to 98% of its GE content, the ME content of dietary lipid was approximately 99% of its DE content, and the NE content of dietary lipid was approximately 90% of its ME content in growing pigs.

Methodologies on estimating the energy requirements for maintenance and determining the net energy contents of feed ingredients in swine: a review of recent work

In the past two decades, a considerable amount of research has focused on the determination of the digestible (DE) and metabolizable energy (ME) contents of feed ingredients fed to swine. Compared with the DE and ME systems, the net energy (NE) system is assumed to be the most accurate estimate of the energy actually available to the animal. However, published data pertaining to the measured NE content of ingredients fed to growing pigs are limited. Therefore, the Feed Data Group at the Ministry of Agricultural Feed Industry Centre (MAFIC) located at China Agricultural University has evaluated the NE content of many ingredients using indirect calorimetry. The present review summarizes the NE research works conducted at MAFIC and compares these results with those from other research groups on methodological aspect. These research projects mainly focus on estimating the energy requirements for maintenance and its impact on the determination, prediction, and validation of the NE content of several ingredients fed to swine. The estimation of maintenance energy is affected by methodology, growth stage, and previous feeding level. The fasting heat production method and the curvilinear regression method were used in MAFIC to estimate the NE requirement for maintenance. The NE contents of different feedstuffs were determined using indirect calorimetry through standard experimental procedure in MAFIC. Previously generated NE equations can also be used to predict NE in situations where calorimeters are not available. Although popular, the caloric efficiency is not a generally accepted method to validate the energy content of individual feedstuffs. In the future, more accurate and dynamic NE prediction equations aiming at specific ingredients should be established, and more practical validation approaches need to be developed.

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.