Fenglai Wang

Nutritional assessment and fate of dna of soybean meal from roundup ready or conventional soybeans using rats

This study was conducted to compare the safety of soybean meal prepared from genetically modified (GM) glyphosate-tolerant (Roundup Ready; RR) soybeans and conventional soybeans. Eighty Sprague-Dawley rats (40 males and 40 females) were randomly allotted to one of four groups according to sex and body weight for a 13-week feeding experiment. The rats were fed corn-based diets containing 60% conventional soybean meal, a mixture of 30% conventional and 30% RR soybean meal, 60% or 90% RR soybean meal. All diets were adjusted to an identical nutrient level except the 90% RR diet. The two soybean meals were similar in chemical analysis and amino acid composition. During the 13-week growth trial, body weight (P < 0.05) and feed intake (P < 0.05) decreased only in rats fed with 90% RR soybean meal at the first week. No treatment-related deaths occurred during the experiment. Gross necropsy findings, haematological or urinalysis values and clinical serum parameters showed no meaningful differences between rats fed the control and RR soybean meals. A 145 bp of cp4 epsps gene specific for the GM constructs from RR soybean meal or a 407 bp of lec gene from endogenous soybean DNA could not be detected in investigated masseter muscle samples. No adverse effects of glyphosate-tolerant soybean meal on rats were seen even at levels as high as 90% of the diet.

Emerging technologies for amino acid nutrition research in the post-genome era

Amino acids (AA) are not only the building blocks of proteins but are also key regulators of metabolic pathways in cells. However, the mechanisms responsible for the effects of AA are largely unknown. With the completion of human and other mammalian genome projects, revolutionary technologies in life sciences characterized by high throughput, high efficiency, and rapid computation are now available for AA nutrition research. These advanced tools include genetics (the genomic variety), epigenetics (stable and heritable changes in gene expression or cellular phenotype that occurs without changes in DNA sequence), transcriptomics (alternative mRNA splicing, microRNAs, and gene transcription), proteomics (protein expression and interactions), metabolomics (metabolite profiles in cells and tissues), and bioinformatics (analysis of metabolic pathways using systems biology approach). These robust, powerful methods can be employed for the analysis of DNA, RNA, protein, and low-molecular-weight metabolites, whose expression and concentration are affected by the interaction between genes and dietary AA. With the omics and other advanced methodologies, we expect that the molecular actions of AA on target tissues can be defined and that optimal dietary recommendations for these nutrients can be devised for individual humans (personalized nutrition) and animals (targeted feeding) in response to changes in physiological and pathological conditions.

Effects of Dietary Conjugated Linoleic Acid on the Fatty Acid Profile and Cholesterol Content of Egg Yolks from Different Breeds of Layers

Brown Dwarf hens and White Leghorn hens were fed corn- and soybean meal-based diets containing 0, 2.5, or 5.0% conjugated linoleic acid (CLA) for 56 d to explore the effects of dietary CLA on the fatty acid profile and cholesterol content of egg yolks from laying hens of different breeds. Four hens were placed in 1 cage, and 3 cages were grouped as 1 replicate, resulting in 6 replicates per treatment. After feeding the experimental diets for 11 d, eggs were collected to determine the fatty acid composition of the egg yolks. From d 54 to 56, eggs were collected to measure the cholesterol content of yolks, and on d 56, a hen was selected randomly from each replicate and bled to determine the cholesterol content in plasma. There was a significant effect of layer breed on layer performance and egg composition. Concentrations of stearic, arachidonic, and docosahexaenoic acids were higher in the yolks of Brown Dwarf hens than in those of White Leghorn hens. Enrichment of cis-11, trans-13 was higher in the yolks of White Leghorns, but cis-10, cis-12 was higher in those of Brown Dwarf hens. In contrast, feed intake and egg weight, as well as yolk weight and its ratio to egg, were decreased by the 5% dietary CLA treatment. Egg production and feed efficiency were not affected by dietary CLA. Concentrations of total CLA and CLA isomers in the yolk lipids increased (P < 0.01) with increasing dietary CLA. Furthermore, yolk cholesterol was increased with increasing dietary CLA (P < 0.01), but this was significantly decreased in Brown Dwarf hens (P < 0.01) by feeding 2.5% CLA. There was no apparent correlation between yolk cholesterol content and serum cholesterol content. In conclusion, Brown Dwarf layers had the breed-specific characteristics of enrichment of CLA isomers and fatty acids in yolk lipids in response to dietary CLA.

Estimation of the net energy requirements for maintenance in growing and finishing pigs

The objective of this experiment was to determine the net energy requirements for maintenance of growing and finishing pigs using regression models. Thirty-six growing (27.38 ± 2.24 kg) and 36 finishing (70.25 ± 2.61 kg) barrows were used and within each phase. Pigs received a corn-soybean meal diet fed at 6 levels of feed intake, which were calculated as 0, 20, 40, 60, 80, or 100% of the estimated ad libitum ME intake (2,400 kJ ME/kg BW(0.6)·d(-1)) of the pigs. Measurements were conducted on 6 pigs per feeding level and per stage of growth. After a 5-d adjustment period, barrows in the fasted treatment were kept in respiration chambers for 2 d to measure the fasting heat production. Barrows in the other treatments were kept individually in respiration chambers for a 5-d balance trial followed by a 2-d fasting period. Heat production (HP) in the fed state was measured and feces and urine were collected in the balance trial. The total HP increased (P < 0.01) with increasing feeding levels. Fasting HP increased (P < 0.01) as previous feeding level increased and was less (P = 0.012) in finishing pigs than growing pigs if calculated per kilogram BW(0.6) per day. When using an exponential regression analysis, ME requirements for maintenance were estimated at 973 and 921 kJ/kg BW(0.6)·d(-1) and NE requirements for maintenance were estimated at 758 and 732 kJ/kg BW(0.6)·d(-1) for growing and finishing pigs, respectively. The efficiencies of using ME for growth and for maintenance were estimated at 66 and 78.7% for growing and finishing pigs, respectively. It is concluded that exponential regression between HP and a wide range of ME intake may be used as a new method to determine the NE requirement for maintenance.

Within-litter variation in birth weight: impact of nutritional status in the sow

Accompanying the beneficial improvement in litter size from genetic selection for high-prolificacy sows, within-litter variation in birth weight has increased with detrimental effects on post-natal growth and survival due to an increase in the proportion of piglets with low birth-weight. Causes of within-litter variation in birth weight include breed characteristics that affect uterine space, ovulation rate, degree of maturation of oocytes, duration of time required for ovulation, interval between ovulation and fertilization, uterine capacity for implantation and placentation, size and efficiency of placental transport of nutrients, communication between conceptus/fetus and maternal systems, as well as nutritional status and environmental influences during gestation. Because these factors contribute to within-litter variation in birth weight, nutritional status of the sow to improve fetal-placental development must focus on the following three important stages in the reproductive cycle: pre-mating or weaning to estrus, early gestation and late gestation. The goal is to increase the homogeneity of development of oocytes and conceptuses, decrease variations in conceptus development during implantation and placentation, and improve birth weights of newborn piglets. Though some progress has been made in nutritional regulation of within-litter variation in the birth weight of piglets, additional studies, with a focus on and insights into molecular mechanisms of reproductive physiology from the aspects of maternal growth and offspring development, as well as their regulation by nutrients provided to the sow, are urgently needed.概要本综述旨在总结仔猪初生重窝内变异对仔猪健康、生长及生产管理造成的不利影响、形成因素、以及改善窝内变异的措施。在现代化高产母猪养殖中, 仔猪初生重窝内变异程度及低初生重猪的比例大幅增加, 导致新生期存活率、生长性能大大降低。初生重窝内变异的影响因素包括母猪排卵率、卵子质量、排卵持续时间、胚胎附植能力、子宫容积、胎盘体积和效率等; 品种差异对仔猪初生重的均匀度也有很大影响。在妊娠的三个关键阶段 (断奶-配种间隔期、妊娠早期和妊娠后期) 进行针对性的营养调控有望一定程度上提高窝内初生重均匀度。目前已被报道的包括: 在配种前母猪日粮中添加葡萄糖或者维生素A, 妊娠后期添加谷氨酰胺均可改善仔猪初生重均匀度, 精氨酸以及支链氨基酸也有提高仔猪初生重一致性的潜能。但总体而言, 目前相关研究相对较少、潜在的分子机制仍不明确, 需要大量深入的研究来加深对妊娠期母体与胎儿发育过程相关生物学事件、营养素作用机制的理解, 为制定出更加科学有效的母猪饲喂措施提供理论基础。

Effect of experimental methodology on fasting heat production and the net energy content of corn and soybean meal fed to growing pigs

The aim of the three experiments was to evaluated methods to predict fasting heat production (FHP) and to compare methods to determine the net energy (NE) of corn and soybean meal (SBM) fed to growing pigs. To estimate heat production (HP), pigs were housed in respiratory chambers for all experiments. In Experiment 1, six barrows (43.0 ±1.4 kg body weight [BW]) were fed a Corn–SBM diet for 20 d. The experimental design consisted of following periods: 7 d adaptation, 5 d ad libitum feeding, 3 d feeding at 2 × metabolisable energy (ME) for maintenance (MEm), 3 d feeding at 1 × MEm and 2 d fasting. The FHP was calculated by extrapolating HP measured at the different feeding levels to zero ME intake. The daily FHP [per kg BW0.6] determined directly after fasting for 24 h and using the regression method was 774 kJ and 694 kJ, respectively. In Experiment 2, 18 barrows (34.3 ± 1.1 kg BW) were randomly allotted to three diets: Diet 1 contained 97.5% corn (direct NE determination of corn); diets 2 and 3 contained 25 % and 15% SBM at the expense of corn, respectively, and were used to calculate the NE of corn by difference. The NE of corn determined directly (13.21 MJ/kg DM) and by difference (13.69 MJ/kg DM) was not different. In Experiment 3, 24 barrows (36.2 ± 1.4 kg BW) were randomly allotted to four diets to determine the effects of different basal diets on the NE content of SBM. The diets were: Basal diet 1 (97.5% corn), Test diet 1 (15% SBM at the expense of corn), Basal diet 2 (contained 72.5% corn and 25% SBM) and Test diet 2 (58% corn and 39.5% SBM). These diets were used to determine the NE of SBM using the Corn–basal diet or the Corn–SBM–basal diet, respectively. It was shown that the estimated NE of SBM did not depend on the used diet (10.04 MJ/kg and 10.62 MJ/kg DM for Basal diet 1 and 2, respectively). In summary, using the regression method to determine FHP results in lower FHP than the fasting method. There was no difference observed in the NE of corn determined directly or by difference, and different basal diets did not affect the NE of SBM.

Determination and Prediction of Digestible and Metabolizable Energy from the Chemical Composition of Chinese Corn Gluten Feed Fed to Finishing Pigs

Two experiments were conducted to determine the digestible energy (DE) and metabolizable energy (ME) contents of corn gluten feed (CGF) for finishing pigs and to develop equations predicting the DE and ME content from the chemical composition of the CGF samples, as well as validate the accuracy of the prediction equations. In Exp. 1, ten CGF samples from seven provinces of China were collected and fed to 66 finishing barrows (Duroc×Landrace×Yorkshire) with an initial body weight (BW) of 51.9±5.5 kg. The pigs were assigned to 11 diets comprising one basal diet and 10 CGF test diets with six pigs fed each diet. The basal diet contained corn (76%), dehulled soybean meal (21%) and premix (3%). The ten test diets were formulated by substituting 25% of the corn and dehulled soybean meal with CGF and contained corn (57%), dehulled soybean meal (15.75%), CGF (24.25%) and premix (3%). In Exp. 2, two additional CGF sources were collected as validation samples to test the accuracy of the prediction equations. In this experiment, 18 barrows (Duroc×Landrace×Yorkshire) with an initial BW of 61.1±4.0 kg were randomly allotted to be fed either the basal diet or two CGF containing diets which had a similar composition as used in Exp. 1. The DE and ME of CGF ranged from 10.37 to 12.85 MJ/kg of dry matter (DM) and 9.53 to 12.49 MJ/kg of DM, respectively. Through stepwise regression analysis, several prediction equations of DE and ME were generated. The best fit equations were: DE, MJ/kg of DM = 18.30–0.13 neutral detergent fiber–0.22 ether extract, with R2 = 0.95, residual standard deviation (RSD) = 0.21 and p<0.01; and ME, MJ/kg of DM = 12.82+0.11 Starch–0.26 acid detergent fiber, with R2 = 0.94, RSD = 0.20 and p<0.01. These results indicate that the DE and ME content of CGF varied substantially but the DE and ME for finishing pigs can be accurately predicted from equations based on nutritional analysis.

Determination and prediction of the net energy content of seven feed ingredients fed to growing pigs based on chemical composition

Two experiments were conducted to determine the net energy (NE) content of various feed ingredients (Exp. 1) and to establish prediction equations for NE for these same ingredients (Exp. 2). In Exp. 1, 36 barrows (27.5 ± 0.5 kg) were assigned to six diets (in a completely randomised design) to give six replicates per diet. The diets were a corn-soybean meal basal diet and five experimental diets containing either wheat, wheat bran, corn dried distillers grains with solubles (cDDGS), canola meal or cottonseed meal. The pigs were housed in six open-circuit chambers (six pigs at a time balanced for dietary treatment) for 16 days, the first 7 days were used for an adaptation to the diets, while for the next 5 days pigs were fed ad libitum (2400 kJ/kg BW0.6·day–1), then fed at 1 × metabolisable energy (ME) for maintenance for 3 days, followed by fasting for 24 h. The NE content of wheat, wheat bran, cDDGS, canola meal, and cottonseed meal were 11.44, 7.78, 10.21, 8.38, and 7.32 MJ/kg DM, respectively. Stepwise regression analysis performed between the chemical composition and the energy value of the ingredients, allowed for the NE to be accurately predicted from chemical characteristics. The best fit equation was: NE = 1.46 + (0.63 × gross energy) – (0.37 × acid detergent fibre), with a R2 of 0.94, a residual standard deviation (RSD) of 0.54 MJ/kg, and P < 0.01. In Exp. 2, 36 barrows (34.6 ± 1.5 kg) were randomly allotted to six diets containing various combinations of corn, soybean meal, wheat, wheat bran, cDDGS, canola meal, or cottonseed meal. The chemical composition of each diet was determined and the results were used to establish prediction equations for the NE in the six diets and 16 diets (including six diets from Exp. 1, six diets from Exp. 2 and four diets from our laboratory published data). The best fit equations were as follows: NE = –0.47 + (0.84 × ME) with an R2 of 0.94, a RSD of 0.20 MJ/kg, and P < 0.01; NE = –10.19 + (0.97 × digestible energy) + (0.08 × starch) + (0.05 × acid detergent fibre) with an R2 of 0.84, a RSD of 0.46 MJ/kg, and P < 0.01, respectively. In summary, the NE of the seven ingredients could be better measured by the respiration calorimetry estimated by substitution method. The NE prediction equation determined based on the chemical characteristics of the test ingredients was better than when determined using the chemical characteristics of the diets.

Effects of Vitamin C Supplementation on Performance, Iron Status and Immune Function of Weaned Piglets

Two experiments were conducted to evaluate the effects of vitamin C supplementation on performance, iron status and immune function of pigs during the 21-day post-weaning period. In experiment one, 48 crossbred pigs (Chester White ‐ Large White ‐ Yorkshire), weaned at 30 days of age and weighing 7.7 ± 0.9kg, were allotted to diets containing either 0 or 300 mg/kg vitamin C. In experiment two, 96 crossbred pigs (Chester White ‐ Large White ‐ Yorkshire), weaned at 20 ± 2 days and weighing 7.1 ± 0.5kg, were allotted to diets containing 0,75 or 300 mg/kg vitamin C. Six replicate pens were assigned to each treatment in experiment one while experiment two had eight replicates. All pens housed two barrows and two gilts. In both experiments, no improvement (P > 0.05) in growth rate, feed intake or feed conversion was observed as a result of vitamin C supplementation. Plasma iron concentration increased (P < 0.10) with increased vitamin C in the diet while free and total iron binding capacity were unaffected by treatment. There were no differences in the intradermal response to the mitogen phytohemaggutinin used as an indicator of cellular immunity (P > 0.05). In trial 2, the plasma levels of the immunoglobulin IgG showed a linear (P = 0.07) increase with increasing levels of vitamin C and the same trend was noted in trial 1. Antibody titers to bovine serum albumin also tended to increase in both trials but the increases were not statistically significant. In conclusion, the overall results of these experiments indicate that weanling pig performance is not improved as a result of vitamin C supplementation. Whether or not vitamin C plays a role in stimulating humoral immune function in pigs requires further study since the results of our experiments do not completely rule out the possibility that such a role exists.

Effects of arginine supplementation during early gestation (day 1 to 30) on litter size and plasma metabolites in gilts and sows

Two experiments were conducted, under typical commercial swine production conditions, to determine effects of dietary arginine supplementation during early gestation on the performance of gilts and sows. In Exp. 1, between d 1 and 30 of gestation, 62 Landrace gilts and 113 sows consumed a corn- and soybean meal-based diet supplemented with 1.3% -arginine HCl or 2.2% -alanine. Total numbers of piglets born ( < 0.05) and born alive ( < 0.01) per litter and litter birth weights of piglets born ( < 0.05) and born alive ( < 0.05) were increased in the arginine group compared with the control. In Exp. 2, 155 multiparous Landrace sows received 1.3% -arginine HCl supplementation between d 1 and 14 (T2; = 41), d 15 and 30 (T3; = 40), or d 1 and 30 (T4; = 37), whereas the control group received 2.2% -alanine supplementation between d 1 and 30 (T1; = 37). Blood samples were randomly obtained from 6 sows per group on d 1, 14, and 28 of gestation to determine plasma concentrations of AA and related metabolites. Total numbers of piglets born ( = 0.084) and born alive ( = 0.080) per litter tended to be higher for sows supplemented with arginine between d 1 and 14 of gestation (T2) than for control sows (T1). Concentrations of arginine and nitric oxide metabolites were greater ( < 0.05) in T4 compared with T1 and T3 on d 14 of gestation and were also greater in T4 compared with T1 and T2 on d 28 of gestation. Plasma concentrations of spermidine ( < 0.001) were increased in T3 and T4 compared with T1 and T2 on d 28. These results indicate that dietary arginine supplementation during early gestation improves the reproductive performance of gilts and sows, possibly via nitric oxide and polyamine-dependent mechanisms.