Effect of variety and drying method on the nutritive value of corn for growing pigs

Nutritional values of soybean meal from different sources in multiparous sows

This study determined the available energy content, apparent total tract digestibility (ATTD) of nutrients, and ileal amino acid (AA) digestibility of soybean meal (SBM) from different sources in non-gestating, non-lactating sows. In Exp. 1, 24 multiparous Landrace × Yorkshire (LY) sows (parity 3 to 5) were allotted to a replicated 12 × 3 Youden square design consisting of 12 diets and 3 periods. The 12 diets included 11 test diets containing SBM from different sources and a corn-based diet. Each period included a 5-d adaptation and a 5-d total fecal and urine collection. In Exp. 2, 8 multiparous LY sows (parity 3 to 5) were allotted to a replicated 4 × 3 Youden square design with 4 diets and 3 periods. The 4 diets included a nitrogen-free diet and 3 SBM diets (3 representative SBM samples were selected from Exp. 1). Our results showed that the coefficient of variation of ether extract, crude fiber, neutral detergent fiber, and acid detergent fiber levels in 11 SBM samples were >20%. There were no differences in digestible energy (DE), metabolizable energy (ME), and the ATTD of gross energy, nitrogen, and neutral detergent fiber values between different SBM samples (P > 0.05). Additionally, no differences in AA digestibility were identified among the 3 representative SBM samples (P > 0.05). In conclusion, there were no differences in DE, ME, and AA digestibility between different SBM samples fed to multiparous non-gestating sows. When formulating diets for sows, it is important to consider the differences in the nutritional value of SBM at different physiological stages.

Determination and Prediction of Available Energy in 13 Cereal Feed Ingredients for Growing Pigs

This study was conducted to develop equations to predict the digestible (DE) and metabolizable energy (ME) for growing pigs by using the chemical compositions of five corn, two wheat and six rice samples. A total of 13 castrated boars were chosen and fed 13 diets formulated with different cereal feed ingredients according to a 13 × 6 Youden square design. The DE and ME contents, the ratio of ME to DE, and the nutrient digestibility among the 13 cereal feed ingredients were different (p < 0.05), and the DE and ME ranged from 13.77 MJ/kg to 17.05 MJ/kg and 13.40 MJ/kg to 16.73 MJ/kg, respectively. The DE and ME were negatively correlated to the NDF (p < 0.10) and ADF (p < 0.05) contents among the test cereals; however, the DE and ME contents were positively correlated with the starch content. Based on the chemical analysis, the models for predicting the DE and ME in the cereal feed ingredients were DE (MJ/kg) = 0.1364 × Starch (%) - 0.2352 × ADF (%) + 11.4467 and ME (MJ/kg) = 0.9838 × DE (MJ/kg) - 0.0165 × CP (%) + 0.0538. In conclusion, the different chemical compositions of different cereal feed ingredients led to large variations in the energy concentration and digestibility of nutrients for growing pigs. The number of cereal samples needs to be further increased to improve the accuracy of the equations for predicting energy contents.

Effects of corn drying and storage conditions on flour, starch, feed, and ethanol production: a review

The objective was to review the effects of the drying and storage conditions of corn on the physical-chemical quality in the processing of starch and flour, in the production of animal feed, and in the industrialization of ethanol. Initially, the review presented an overview of the post-harvest stages of corn grains, highlighting drying and storage. The main drying and storage methods used for corn grains were presented. Among the drying conditions, the air temperature was the main factor that affected the properties of starch, flour, feed, and ethanol produced from corn. It was verified that the corn grains submitted to drying at temperatures below 60 °C obtained better results in the industry. In storage, in addition to the storage time, factors such as temperature and moisture content of the grains affected the physical-chemical quality of the processed products. In this stage, the moisture content below 14% and the storage temperature below 25 °C conserved the physical-chemical quality of the grains and obtained better processing results. Further studies are needed to assess the effects of the drying and storage conditions of corn on the properties of flour, starch, animal feed, and, mainly, ethanol production.

Graphical abstract

Effects of gradually increasing drying temperatures on energy aspects, fatty acids, chemical composition, and in vitro ruminal fermentation of acorn

Acorns are commonly used to meet energy, protein, and mineral needs of livestock in various parts of the world. However, since acorns have quite a high moisture content at harvest, they should be stored as dried to prevent loss of nutrients and spoilage throughout storage periods. The aim of this study is to determine the drying kinetics, color, energy aspects, crude protein, crude ash, crude oil, fatty acid composition, ADF, NDF, condensed tannin, and mineral composition properties of acorns dried at gradually increasing drying temperatures. Drying processes were carried out in an air-convective dryer at temperatures of 40, 60, 80, 100, and 120 °C. The Logistic model was identified as the best model for describing current drying conditions. Increasing drying temperatures reduced L* (lightness) values and increased thermal efficiency and effective moisture diffusion values. In terms of energy efficiency, the best outcomes were achieved at 80 °C and 120 °C drying temperatures. Drying temperatures had highly significant effects on nutritional traits of acorn samples. Increasing drying temperatures increased fiber content, gas-methane production, and energy values and reduced crude protein and oil contents. Some minerals decreased and some others increased with increasing drying temperatures. Increasing drying temperatures caused slight changes in fatty acid compositions. In terms of animal drying and feeding characteristics, it was determined that a drying temperature of 80 °C was ideal for acorn drying.

Effects of corn hardness and drying temperature on digestibility of energy and nutrients in diets fed to growing pigs

Two experiments were conducted to test the hypothesis that corn kernel hardness and drying temperature influence the ileal digestibility of starch and amino acids (AA), as well as apparent total tract digestibility (ATTD) of gross energy (GE) and total dietary fiber (TDF) in diets for growing pigs. Two corn varieties with average or hard endosperm were grown and harvested under similar conditions, and after harvest, each variety was divided into 2 batches that were dried at 35 and 120 °C, respectively. Therefore, four batches of corn were used. In experiment 1, 10 pigs (67.00 ± 2.98 kg) with a T-cannula installed in the distal ileum were allotted to a replicated 5 × 5 Latin square design with 5 diets and 5 periods giving 10 replicates per diet. A nitrogen-free diet and four diets containing each source of corn as the only AA source were formulated. Results indicated that neither variety of corn nor drying temperature influenced apparent ileal digestibility of starch in the grain. The standardized ileal digestibility of most AA was less (P < 0.05) in corn dried at 120 °C compared with corn dried at 35 °C resulting in concentrations of most standardized ileal digestible AA being less (P < 0.05) in corn dried at 120 °C than in corn dried at 35 °C. In experiment 2, 40 pigs (20.82 ± 1.74 kg) were housed in metabolism crates and allotted to 4 diets with 10 replicate pigs per diet. The four corn-based diets used in experiment 1 were also used in experiment 2. Feces and urine were collected using the marker-to-marker approach with 5-d adaptation and 4-d collection periods. Results indicated that diets containing hard endosperm corn had greater (P < 0.05) ATTD of TDF than diets containing average endosperm corn. The ATTD of GE in hard endosperm corn was also greater (P < 0.05), and concentrations of digestible energy and metabolizable energy in hard endosperm corn were greater (P < 0.01) than in average endosperm corn. Diets containing corn dried at 120 °C had greater (P < 0.05) ATTD of TDF compared with diets containing corn dried at 35 °C; however, drying temperature did not influence the ATTD of GE. In conclusion, endosperm hardness did not influence the digestibility of AA and starch; however, drying corn at 120 °C reduced digestible AA concentrations. Hard endosperm corn had greater ATTD of GE and TDF, but drying temperature did not influence energy digestibility.

Determination and prediction of the available energy and amino acids digestibility of full-fat soybean fed to growing pigs

Two experiments were conducted to determine the digestible energy and metabolizable energy contents, as well as the apparent ileal digestibility and standardized ileal digestibility of amino acids in full-fat soybean fed to growing pigs. Ten full-fat soybean samples were collected from different areas in China and used in two experiments in this study. In Exp. 1, 66 growing pigs (initial body weight = 18.48 ± 1.2 kg) were randomly allotted to 1 of 11 diets (n = 6) including a corn basal diet and 10 experimental diets formulated by replacing the corn with 30% full-fat soybean. In Exp. 2, 11 growing pigs (initial body weight = 50.45 ± 3.2 kg) were surgically equipped with a T-cannula in the distal ileum and arranged in a 6 × 11 Youden square design with 11 diets and 6 periods. The diets included an N-free diet based on cornstarch and sucrose and 10 experimental diets formulated with full-fat soybeans as the sole source of amino acids. Chromic oxide was added into the diets as an indigestible maker to calculate the digestibility of the amino acids. Results showed that there was considerable variation in neutral detergent fiber, acid detergent fiber, and trypsin inhibitor contents in the 10 full-fat soybean samples with a coefficient of variation greater than 10%. On a dry matter basis, the averaged digestible energy and metabolizable energy values in the 10 full-fat soybean samples were 4,855 and 4,555 kcal/kg, respectively, both were positively correlated with the ether extract content. The best-fitted prediction equations for digestible energy and metabolizable energy of full-fat soybean were: digestible energy, kcal/kg = 3,472 + 94.87 × ether extract - 97.63 × ash (R2 = 0.91); metabolizable energy, kcal/kg = 3,443 + 65.11 × ether extract - 36.84 × trypsin inhibitor (R2 = 0.91). In addition, all full-fat soybean samples showed high apparent ileal digestibility and standardized ileal digestibility values in amino acids and were all within the range of previously published values. Those values significantly varied among different samples (P < 0.05) for most amino acids, except for glycine and proline. In conclusion, full-fat soybean is a high-quality protein ingredient with high ileal digestibility of amino acids when fed to growing pigs, and the metabolizable energy value of full-fat soybean could be predicted based on its ether extract and trypsin inhibitor contents.

Corn kernel hardness, drying temperature and amylase supplementation affect live performance and nutrient utilization of broilers

Drying temperature (DT) of corn can influence its nutritional quality, but whether this is influenced by endosperm hardness is not clear. Two parallel experiments were conducted to investigate the effects of 2 yellow dent corn hybrids with average and hard kernel hardness, dried at 3 temperatures (35, 80, and 120°C), and 2 supplementation levels of an exogenous amylase (0, 133 g/ton of feed) on live performance, starch and protein digestibility, and energy utilization of Ross 708 male broilers. Twelve dietary treatments consisting of a 2 × 3 × 2 factorial arrangement were evaluated using 3-way ANOVA in a randomized complete block design. In Experiment 1, a total of 1,920 male-chicks were randomly allocated to 96 floor pens, whereas 480 day-old chicks were distributed among 96 cages for Experiment 2. At 40 d, interaction effects (P < 0.05) were detected on BWG, FCR, and flock uniformity. Supplementation with exogenous amylase resulted in heavier broilers, better FCR and flock uniformity, only in the diets based on corn dried at 35°C. Additionally, interaction effects were observed on FCR due to kernel hardness and DT (P < 0.01), kernel hardness and amylase supplementation (P < 0.001), and DT and amylase supplementation (P < 0.05). Exogenous amylase addition to the diets based on corn with an average hardness improved FCR up to 2 points (1.49 vs. 1.51 g:g) whereas there was no effect of amylase on FCR of broilers fed diets based on corn with hard endosperm. Total tract retention of starch was increased (P < 0.05) in broilers fed diets based on corn with average kernel hardness compared to hard kernel. Corn dried at 80 and 120°C had up to 1.21% points less starch total tract retention than the one dried at 35°C. Supplementing alpha-amylase resulted in beneficial effects for broiler live performance, energy utilization, and starch total tract digestibility results. Treatment effects on starch characteristics were explored. Corn endosperm hardness, DT and exogenous amylase can influence the live performance of broilers. However, these factors are not independent and so must be manipulated strategically to improve broiler performance.

Corn drying temperature, particle size, and amylase supplementation influence growth performance, digestive tract development, and nutrient utilization of broilers

Broiler live performance may be influenced by postharvest corn drying temperature, and results could depend on particle size after grinding. The supplementation with an exogenous amylase may improve performance parameters, but responses to enzymes are also affected by particle size. Two parallel experiments were conducted to evaluate the effects of hard-kernel corn dried at 2 temperatures (35°C and 120°C), ground at 2 particle sizes (coarse or fine), and 3 supplementation levels (0, 133, and 266 g ton-1) of an exogenous amylase on live performance, gastrointestinal organ development, energy utilization, and nutrient digestibility. Twelve dietary treatments resulting from a 2 × 2 × 3 factorial arrangement of drying temperature, particle size, and amylase supplementation were evaluated in both experiments. A total of 1,920 day-old male chicks were randomly allocated to 96 floor pens, while 480 chicks were distributed among 4 battery brooder units. Ileal and fecal samples were collected to determine energy utilization and nutrient digestibility using titanium dioxide as inert marker. At 42 D, organs were collected, and relative weight or length was determined. Data were analyzed using a three-way ANOVA in a randomized complete block design. Feeding fine corn-based diets showed improvements on live performance for both studies. At 40 D, supplementing 266 g ton-1 of amylase improved feed conversion ratio (P < 0.05) by 1 point compared to chickens that consumed nonsupplemented diets and feed with amylase at 133 g ton-1. Broilers fed coarse corn-based diets had heavier gizzard (P < 0.001) and liver (P < 0.05) than chickens that consumed fine corn-based diets. In addition, starch digestibility was improved by amylase (P < 0.05) at 133 g ton-1 and by feeding coarse corn-based diets (P = 0.06). For chicks raised in cages (16 D), AMEn was increased (P < 0.01) by amylase supplementation regardless of its inclusion level. In conclusion, drying temperature and particle size interactions influenced broiler live performance, gastrointestinal organ development, nutrient digestibility, and energy utilization, and these parameters were improved by supplementing amylase.

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.

Regression Equations of Energy Values of Corn, Soybean Meal, and Wheat Bran Developed by Chemical Composition for Growing Pigs

The objectives of this study were to determine the chemical compositions, digestible energy (DE), and metabolizable energy (ME) in corn, soybean meal (SBM) and wheat bran (WB) fed to growing pigs, and to develop regression equations for predicting DE and ME. Three separate experiments were conducted to determine DE and ME of corn, SBM, and WB. The DE and ME in corn were determined directly using 10 barrows allotted to a replicated 5 × 5 Latin square design, and the diets were formulated with one of 10 corn samples. The DE and ME in SBM and WB were determined by difference using two corn basal diets and 10 corn-SBM or 10 corn-SBM-WB diets, which were allotted to a replicated 6 × 6 Latin square design. Ten corn samples were obtained from the main corn producing areas of China. Ten SBM samples were obtained from nine different crushing facilities in nine provinces in China. Ten WB samples were collected from different feed mills of China. Samples were analyzed for dry matter (DM), crude protein (CP), ether extract (EE), ash, neutral detergent fiber (NDF), acid detergent fiber (ADF), gross energy (GE), and soluble carbohydrates (SCHO). The best-fit equations for corn were DE (MJ/kg DM) = 20.18 - 0.76 × EE (%) and ME (MJ/kg DM) = 5.74 + 1.11 × DE (MJ/kg DM) - 0.33 × CP (%) - 0.07 × SCHO (%). The best-fit equations for SBM were DE (MJ/kg DM) = 42.91 - 3.43 × Ash (%) - 0.20 × NDF (%) + 0.09 × ADF (%) and ME (MJ/kg DM) = -21.67 + 0.89 × DE (MJ/kg DM) - 1.06 × GE (MJ/kg DM). The best-fit equations for WB were DE (MJ/kg DM) = -7.09 + 1.54 × CP (%) - 0.25 × NDF (%) - 0.32 × ADF (%) + 0.23 × Ash (%) and ME (MJ/kg DM) = 0.02 + 0.96 × DE (MJ/kg DM). The chemical composition of corn, SBM, and WB can vary substantially from zone to zone, resulting in considerable variation in its available energy value for pig. The DE and ME of corn, SBM and WB for growing pigs can be predicted based on their chemical compositions.

Nutritional evaluation of different varieties of sorghum and the effects on nursery pig growth performance

Five experiments were conducted to determine the standardized total tract digestibility (STTD) of P, digestible energy (DE), metabolizable energy (ME), and standardized ileal digestibility (SID) of amino acids (AA) in three sorghum varieties compared with corn and to determine the effects of sorghum varieties on nursery pig growth. In exp. 1, 48 barrows (initially 18.6 kg) were housed individually in metabolism crates. Treatments were arranged in a 2 × 4 factorial evaluating two levels of microbial phytase (0 or 500 units/kg) and four grain sources (corn, high-lysine, red, or white sorghum). Added phytase improved (P < 0.05) STTD of P in all ingredients, but was not different among the grains. In exp. 2, the DE and ME in the three sorghum varieties were not different from corn. In exp. 3, 10 growing barrows (initially 25.9 kg) with a T-cannula in the terminal ileum were used. Standardized ileal digestible Lys, Met, Thr, and Val were greater (P < 0.05) in corn than in the sorghum-based diets with no differences among the sorghum varieties. In exp. 4, 160 pigs (initially 6.3 kg) were randomly allotted to one of four dietary treatments with five pigs per pen and eight replicate pens per treatment in a 20-d experiment. Dietary treatments included corn or the three sorghum varieties, where the varieties of sorghum replaced corn on an SID Lys basis. No differences among treatments were observed in any growth performance parameters. In exp. 5, treatments consisted of a corn-based diet, a diet based on conventional sorghum (a mixture of red and white sorghum), and four diets with high-lysine sorghum containing increasing amounts of feed-grade AA, replacing soybean meal. Overall, pigs fed the high-lysine sorghum diet with the greatest amount of added feed-grade AA had the poorest gain:feed ratio (G:F; P < 0.05) compared with pigs fed all the other experimental diets. Within those fed the high-lysine sorghum and feed-grade AA, average daily gain, final body weight (linear, P < 0.10), and G:F (linear, P < 0.01) decreased as feed-grade AA increased. In summary, no differences in STTD of P or in DE and ME were observed among the grain sources. The SID AA values for the three sorghum varieties were not different; however, they were all lower than for corn. These results indicate that these varieties of sorghum can successfully replace corn in nursery pig diets if diets are formulated to account for differences in AA digestibility.

Physicochemical properties and energy content of yellow dent corn from different climatic origins in growing pigs

Objective

The objective of this study was to determine the digestible energy (DE) and metabolizable energy (ME) of yellow dent corn sourced from different meteorological origins fed to growing pigs and develop equations to predict the DE and ME of yellow dent corn from southwestern China.

Methods

Sixty crossbred barrows were allotted to 20 treatments in a triplicate 20×2 incomplete Latin square design with 3 replicated pigs per dietary treatment during 2 consecutive periods. Each period lasted for 12 days, and total feces and urine during the last 5 days of each period were collected to calculate the energy contents.

Results

On dry matter (DM) basis, the DE and ME in 20 corn grain samples ranged from 15.38 to 16.78 MJ/kg and from 14.93 to 16.16 MJ/kg, respectively. Selected best-fit prediction equations for DE and ME (MJ/kg DM basis) for yellow dent corn (n = 16) sourced from southwestern China were as follows: DE = 28.58–(0.12×% hemicellulose)+(0.35×% ether extract)–(0.83×MJ/kg gross energy)+(0.20×% crude protein)+(0.49×% ash); ME = 30.42–(0.11×% hemicellulose)+(0.31×% ether extract)–(0.81×MJ/kg gross energy).

Conclusion

Our results indicated that the chemical compositions, but not the meteorological conditions or physical characteristics could explain the variation of energy contents in yellow dent corn sourced from southwestern China fed to growing pigs.

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.

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.

Determination of the energy contents and nutrient digestibility of corn, waxy corn and steam-flaked corn fed to growing pigs

Objective

The research was conducted to determine the digestible (DE) and metabolizable energy (ME) contents as well as the apparent total tract digestibility (ATTD) of nutrients in corn, waxy corn and steam-flaked corn fed to growing pigs.

Methods

Eighteen growing pigs with initial body weight of 15.42±1.41 kg were randomly allotted to three diets including a corn diet, a waxy corn diet and a steam-flaked corn diet in a completely randomized design. Each treatment contained six replicates. The experiment lasted for 12 days, which comprised 7-d adaptation to diets followed by a 5-d total collection of feces and urine. The energy contents and the nutrient digestibility in three ingredients were calculated using direct method.

Results

Compared to normal corn, both the amylose and dietary fiber contents in waxy corn were numerically lower, but the starch gelatinization degree was numerically greater. Moreover, the DE and ME contents as well as the ATTD of neutral detergent fiber and acid detergent fiber (ADF) in waxy corn were significantly greater (p<0.05) than those in normal corn when fed to growing pigs. Furthermore, the steam-flaked corn had greater (p<0.05) DE and ME contents, and ATTD of ether extract and ADF compared to normal corn.

Conclusion

Both variety and processing procedure have influence on chemical compositions, energy contents and nutrient digestibility of corn. The waxy corn and steam-flaked corn had greater degree of starch gelatinization and DE and ME contents compared to normal corn when fed to growing pigs.

Effect of inclusion level of corn germ meal on the digestible and metabolizable energy and evaluation of ileal AA digestibility of corn germ meal fed to growing pigs

Two experiments were conducted to investigate the effect of inclusion level of corn germ meal (CGM) on the DE and ME values of CGM and to evaluate the ileal AA digestibility of CGM fed to growing pigs. In Exp. 1, 42 barrows (63.8 ± 2.1 kg BW) were allotted to seven diets in a completely randomized design with six replicates per diet. Diets included a corn-soybean meal (SBM) diet and six additional diets containing 4.85%, 9.70%, 19.40%, 29.10%, 38.80%, or 48.50% CGM. Pigs were fed twice daily, at 0730 and 1630 hours, at a level of 4% of BW, and feces and urine were collected for 5 d. The apparent total tract digestibility (ATTD) of DM, OM, CP, acid-hydrolyzed ether extract, and the DE and ME in diets linearly decreased (P < 0.01) as dietary CGM increased. Inclusion level of CGM had no effect on the DE and ME values of CGM. On a DM basis, the concentration of DE and ME varied from 3,396 to 3,747 kcal/kg and 3,107 to 3,502 kcal/kg, respectively. In Exp. 2, 11 crossbred barrows (30.4 ± 2.9 kg BW) with a T-cannula in the distal ileum were allotted to an 11 × 6 Youden square design with 11 diets and 6 period, which included an N-free diet and 10 CGM test diets. Chromic oxide (0.3%) was included in all diets as an indigestible marker. Pigs were fed daily at 4% of BW during each period, which consisted of 5 d of diet adaptation followed by 2 d of digesta collection. The apparent ileal digestibility (AID) of Ile, Thr, and Ala and the standardized ileal digestibility (SID) of CP and Ile varied (P < 0.01) among the 10 CGM. The AID of CP and all AA except Pro and Tyr, and the SID of all AA except Pro were the greatest (P < 0.05) in sample 7. The AID and SID of CP averaged 40.47% and 64.75%, respectively, and varied from 32.30% to 54.87% and from 57.48% to 72.15%, respectively. The average SID of Lys, Met, Thr, and Trp was 65.61%, 76.15%, 65.29%, and 60.17%, respectively, with a SEM of 4.49, 2.40, 5.95, and 6.82, respectively. The average SID of Pro was 101.76%, with an SEM of 17.26. Increasing dietary CGM decreased the ATTD of nutrients, the DE and ME values of diets but CGM. The AID and SID of AA in CGM are low but source dependent, and CGM may be fed to pigs as an protein-rich feedstuff.

Effects of variety and storage duration on the nutrient digestibility and the digestible and metabolisable energy content of maize fed to growing pigs

The objective of this research was to determine the effects of variety and storage duration on the nutrient digestibility and the digestible (DE) and metabolisable (ME) energy content in maize when fed to growing pigs. Four maize varieties (LS1, LS2, LS3 and LS4) were hand-harvested from the same growing area in China in early October of 2012. The samples were sun dried to about 14% moisture content and then stored in the warehouse of the Fengning Pig Experiment Base at China Agricultural University for 0, 3 or 10 months. Twenty-four barrows of about 33 kg body weight were used and allotted to a completely randomised block design with four diets and six replicate pigs per diet. Pigs were individually housed in metabolic crates. The four experimental diets were formulated by mixing 96.8% of each variety of maize with 3.2% vitamins and minerals. A 5-day collection period followed a 7-day diet acclimation period. The results indicated that the DE and ME contents of maize and the apparent total tract digestibility (ATTD) of organic matter (OM), dry matter, gross energy (GE), neutral detergent fibre, acid detergent fibre (ADF), crude protein (CP) and ether extract (EE) were significantly (p < 0.05) influenced by maize variety and storage duration. With an extension of storage duration from 0 to 10 months, the DE and ME of maize and the ATTD of OM, GE, ADF, CP and EE changed in a quadratic manner (p < 0.05), and 3 months of storage exceeded 0 months of storage by 1.84%, 1.43%, 0.31%, 0.32%, 15.37%, 2.11% and 5.02%, respectively. The DE, ME of maize and the ATTD of OM, GE, ADF, CP and EE decreased by 3.67%, 6.00%, 0.97%, 1.40%, 30.54%, 3.92% and 20.93%, respectively, at 10 months of storage compared to 3 months of storage. No interaction was observed between maize variety and storage duration in DE and ME contents in maize. In conclusion, under the conditions of this study, most of the nutrient digestibility and the DE and ME contents of maize increased from 0 to 3 months and decreased from 3 to 10 months.

The Nutritive Values in Different Varieties of Corn Planted in One Location Fed to Growing Pigs over Three Consecutive Years

This experiment was conducted to determine the effect of variety and planting year on the nutritive values of corn fed to growing pigs. Four corn varieties examined in this experiment were planted in the same village located in Longhua County, Heibei Province, China, in 2012, 2013, and 2014, respectively. During each year, corn was hand-harvested in early October and sun dried to about 14% moisture content. Three batches of twenty-four barrows (33.27±4.30, 31.88±2.93, 34.21±3.81 kg body wight [BW] in 2012, 2013, and 2014, respectively) were used and allotted to a complete block design with 4 diets and 6 replicate pigs per diet. Pigs were individually placed in metabolic crates. The four experimental diets were formulated by mixing each variety of corn and vitamins and minerals, respectively. A five-day collection period followed a seven-day diet acclimation period. The results indicated that variety of corn significantly influenced the available energy content (digestible energy [DE] on dry matter basis, p<0.05; metabolizable energy (ME) on dry matter basis, p<0.05, respectively), and the apparent total tract digestibility (ATTD) of organic matter (p<0.01), dry matter (p<0.05), gross energy (p<0.05), neutral detergent fiber (p<0.01), acid detergent fiber and ether extract (p<0.05). The planting year also significantly influenced the available energy contents (DE on dry matter basis, p<0.05; ME on dry matter basis, p<0.01, respectively) and the ATTD of neutral detergent fiber (p<0.01), acid detergent fiber (p<0.01), crude protein (p<0.01), and ether extract (p<0.01). No interaction was observed between the variety and planting year in DE and ME contents in corn. In conclusion, the variety and planting year significantly influenced the available energy and nutrient digestibility of corn fed to growing pigs.