Evaluation of dry matter intake and daily weight gain predictions of the Cornell Net Carbohydrate and Protein System with local breeds of beef cattle in China

Three feeding trials with different dietary treatments were conducted to evaluate predictions of dry matter intake and average daily gain of Chinese local beef cattle by Cornell Net Carbohydrate and Protein System (CNCPS) version 5.0. In Trial 1, 60 growing Jin Nan yellow steers (local yellow cattle breed originated from Shanxi Province) were assigned to two treatments with five pens in each treatment and six animals in each pen. Trial 2 was conducted with 72 Lu Xi yellow growing steers (local yellow cattle breed originated from Shandong Province) in 12 conventional pens. These animals were assigned to four treatments with six animals in each pen. In Trial 3, 60 Lu Xi yellow steers were allocated to four treatments with five animals in each pen. Average daily dry matter intake (DMI) for each steer was measured as a mean of each pen. All the data about animals, environment, management and feeds required by the CNCPS model were collected, and model predictions were generated for animals of each pen. Model predictions were evaluated by mean bias, mean square prediction error (MSPE) and regression between the observed and predicted values. Animals in 9 of 10 treatments showed a very close model-predicted DMI values to the observed. In another treatment, animals had a mean bias of −0.72 kg DM/day (TRT 10 in Trial 3). With overall data included, the regression equation between observed and predicted DMI was: Y_OBS = 1.10X_CNCPS − 0.78 (R² = 0.82; P<0.0001), with an intercept not different (P=0.32) from zero, but a slope still different (P<0.0001) from 1. Although the model-predicted ADG values were very close to the observed values in all trials, most of the predicted values were always lower than the observed values with absolute mean bias less than 0.2. When all data were pooled, the regression equation between observed and predicted ADG was: Y_OBS = 1.07X_CNCPS + 0.02 (R² = 0.73; P<0.0001), with an intercept not different from zero (P=0.88), but a slope that differed from unity (P<0.0001). Results suggest that the CNCPS model is an acceptable model to predict dietary DM intake and average daily gain of Chinese local beef cattle breeds. Further studies are warranted to introduce model adjustment for Chinese conditions.     

Need for escape protein by grazing cattle

Grazing cattle require rumen degradable protein to meet the needs of the microbial population and rumen undegradable protein to meet the productive needs of the animal. The need for rumen degradable protein is about 130 g kg⁻¹ of digestible organic matter. However, when low-quality forage is consumed, rate of passage is reduced, microbial growth rate is reduced and conversion efficiency of microbial growth is reduced. This probably lowers the rumen degradable protein requirement. Escape protein is necessary to meet cattle requirements for growth or lactation. Microbial protein is usually adequate for animals at or near maintenance. The protein in both cool-season and warm-season grasses is highly degraded. Therefore, growing cattle and lactating cows responded to supplemental escape protein. Knowledge of the rumen degradable and undegradable protein contents of grazed forages is essential to more precisely predict animal performance and the animal response to protein supplements.     

Distillers grains as an energy source and effect of drying on protein availability

The use of distillers byproducts as energy sources would expand the market for these byproducts. Drying of these byproducts may produce changes that affect the nutritional value. A series of experiments was conducted to evaluate distillers byproducts as an energy source for finishing cattle and to compare wet vs. dried byproducts. The energy value of wet distillers byproducts was 132 to 174% the value of dry rolled corn for finishing cattle when the byproducts were fed as 40% of the diet dry matter. Distillers dried grains plus solubles were 130% the energy value of corn. Acid detergent insoluble nitrogen level of the dried grains did not affect feeding value. Distillers dried grains plus solubles were equal in protein value to wet byproducts when fed to growing calves. Acid detergent insoluble nitrogen level did not affect protein utilization of dried distillers byproducts.     

莆田黑猪肠道菌群的动态变化及其对平均日增重的影响

本研究旨在揭示莆田黑猪肠道菌群在不同生长阶段的动态变化情况并探究其对平均日增重的影响。

本研究采集了60头莆田黑猪60日龄和240日龄时的粪便样品, 利用16S rRNA基因测序分析了肠道菌群组成随时间的变化。随后, 通过关联分析鉴别了与平均日增重显著相关的微生物类群和功能途径。

16S rRNA基因测序结果表明, 莆田黑猪肠道菌群α-多样性随着日龄增大而显著升高。相反, β-多样性则显著降低。随日龄增加, 肠道菌群中厚壁菌门的相对丰度显著降低, 圣诞岛盐菌门的相对丰度显著升高(P < 0.01)。此外, 普雷沃菌NK3B31、螺旋菌属、罗氏菌属、乳酸杆菌属和普雷沃菌UCG-003在60日龄组肠道菌群中显著富集, 密螺旋体属2则在240日龄组肠道菌群中具有更高的丰度。关联分析结果显示, 8个OTUs和19条功能途径与平均日增重显著相关, 与平均日增重相关的细菌可能通过参与复杂性多糖降解、短链脂肪酸代谢、免疫功能调控和炎症反应等过程影响莆田黑猪的生长。

本研究发现莆田黑猪肠道菌群在不同生长阶段会发生明显改变, 肠道菌群的变化对平均日增重具有重要影响。

     

Effect of growth rate from 6 to 16 months of age on sexual development and reproductive function in beef bulls

Sexual development and reproductive function were studied in 22 Angus × Charolais and 17 Angus bulls from 6 to 16 mo of age. Associations of average daily gain (ADG) and body weight with ages at puberty and at maturity (satisfactory semen quality), scrotal circumference, paired-testes volume and weight, testicular vascular cone diameter and fat thickness, scrotal temperature, sperm production and morphology, and testicular histology, were determined. There were no significant correlations between cumulative average daily gain and any of the end points investigated. Body weight at various ages was negatively correlated with ages at puberty and maturity in Angus × Charolais bulls, positively correlated with paired-testes weight in Angus × Charolais and Angus bulls, and positively correlated with seminiferous tubule volume in Angus bulls (P < 0.05). Semen quality improved gradually with age and the interval between puberty and maturity (mean ± SD; 309.4 ± 29.7 and 357 ± 42 days of age) was approximately 50 days. Age, weight, scrotal circumference, and paired-testes volume were all good predictors of pubertal and mature status, with moderate to high sensitivity and specificity (71.6% to 92.4%). In summary, growth rate between 6 and 16 mo of age did not affect sexual development and reproductive function in beef bulls. However, greater body weight at various ages was associated with reduced age at puberty and maturity, and with larger testes at 16 mo of age, indicating that improved nutrition might be beneficial, but only when offered before 6 mo of age. Average daily gains of approximately 1 to 1.6 kg/day did not result in excessive fat accumulation in the scrotum, increased scrotal temperature, or reduction in sperm production and semen quality, and could be considered “safe” targets for growing beef bulls.     

基于氨基酸分类的基本氨基酸秩序的研究

在分析了基本氛基酸分类的基础上,提出基本氛基酸存在着一种参考排列秩序,以此固定的氛基酸排列秩序为参考标准,分析蛋白质一级结构相对此参考秩序的变化规律,能够找到构成蛋白质的二级结构的某些信息．     

Impact of separating amino acids between plasma, extracellular and intracellular compartments on estimating protein synthesis in rodents

Summary. Three models representing different separations of amino acid sources were used to simulate experimental specific radioactivity data and to predict protein fractional synthesis rate (FSR). Data were from a pulse dose of ¹⁴C-U Leu given to a non-growing 20 g mouse and a flooding dose of ³H Phe given to a non-growing 200 g rat. Protein synthesis rates estimated using the combined extracellular and intracellular (Ec + Ic) source pool and extracellular and plasma (Ec + Pls) source pool mouse models were 78 and 120% d⁻¹ in liver, 14 and 16% d⁻¹ in brain and 15 and 14% d⁻¹ in muscle. Predicted protein synthesis rates using the Ec + Ic, Ec + Ic + Tr (combined extracellular, intracellular and aminoacyl tRNA source pool) and Ec + Pls rat models were 57, 3.4 and 57% d⁻¹ in gastrocnemius, 58, 71 and 62% d⁻¹ in gut, 8.3, 8.4 and 7.9% d⁻¹ in heart, 32, 23 and 25% d⁻¹ in kidney, 160, 90 and 80% d⁻¹ in liver, 57, 5.5 and 57% d⁻¹ in soleus and 56, 3.4 and 57% d⁻¹ in tibialis. The Ec + Ic + Tr model underestimated protein synthesis rates in mouse tissues (5.0, 27 and 2.5% d⁻¹ for brain, liver and muscle) and rat muscles (3.4, 5.5 and 3.4% d⁻¹ for gastrocnemius, soleus and tibialis). The Ec + Pls model predicted the mouse pulse dose data best and the Ec + Ic model predicted the rat flooding dose data best. Model predictions of FSR imply that identification and separation of the source specific radioactivity is critical to accurately estimate FSR. Received June 11, 2000 Accepted September 26, 2000     

Comparative study on microwave and conventional methods for protein hydrolysis in food

Summary A rapid microwave hydrolysis procedure was developed for amino acid determination in food. The hydrolysis was performed with 6M HCl in sealed vessels using a microwave digestion system.Bovine Serum Albumin was chosen as a model protein to compare its theoric amino acid sequence with the experimental results obtained after hydrolysis by both the traditional oven heating and the microwave methods. Furthermore the selected microwave methods were carried out on different food matrices (cheese and durum wheat) and the obtained data were compared with the traditional method results.This comparative study shows that the rapid microwave hydrolysis is as accurate and precise as the traditional hydrolysis for determining amino acids in food.These results were presented at the Third International Congress on Amino Acids, Vienna, August 23–27th, 1993.     

Amino acid flooding doses for measuring rates of protein synthesis

Summary The development, advantages and disadvantages of using the amino acid flooding dose technique to determinein vivo rates of protein synthesis are examined in this review. A discussion of the use of this procedure in animals greater than 5 kg is included. The flooding dose procedure reduces the disparity between isotope enrichment in different amino acid precursor pools, which should theoretically improve the precision and accuracy of protein synthesis measurements. However, the possibility must be considered that the large doses of amino acids injected or infused in conjunction with this technique may influence protein turnover due to attendant metabolic effects. Therefore, a judicious choice of an amino acid and an evaluation of the experimental parameters involved in this procedure are required to optimize the accuracy of results obtained.Scientific Paper No. 710. Agriculture Canada, Lacombe Research Station, Bag Service 5000, Lacombe, Alberta T0C 1S0.     

Old breeds,new solutions? Effects of two different traditional sire breeds on skin lesions,tail lesions,tail losses,performance and behaviour of rearing pigs

Some studies indicated a relationship between modern, fast-growing, lean-meat-producing hybrid pigs and the occurrence of tail-biting, one of the major issues of conventional pig husbandry. Therefore, this study investigated the effects of different local, traditional sire breeds on the behaviour and performance of rearing pigs. Between December 2019 and November 2020, a total of 1 561 piglets were weaned from hybrid sows (Bundes Hybrid Zucht Programm (BHZP) Landrace × BHZP Large White) that were paired with either Swabian-Hall (SH), Bentheim Black Pied (BB) or BHZP-Piétrain (Pi) boars. Tails of the piglets were left intact (43.5%) or docked (56.5%), and male piglets were castrated. Piglets were conventionally reared on fully slatted plastic flooring in mixed-sex groups. Starting one day after weaning, skin lesions were scored once per pig, and tail lesions and losses were scored weekly until the end of rearing. The average daily gain was documented for the suckling and rearing period. The activity behaviour of eight focal pens was analysed using video recordings. Differences between modern and traditional breeds were found in this study for so-called aggressive and non-aggressive biting pronounced by skin and tail lesions and tail losses. Significantly fewer BB pigs had severe skin lesions on the front body than SH or Pi pigs (P < 0.05). Additionally, piglets that were classified as light (<5.6 kg) at weaning showed skin lesion scores of 0 more often than piglets that were classified with a medium (≥5.6–≤8.3 kg) or heavy (>8.3 kg) weaning weight (P < 0.05). In the first half of the rearing period, significantly more BB pigs were assessed as having no tail lesions and tail losses than SH and Pi pigs (P < 0.01). However, these differences disappeared in the second half of rearing. Either docked or undocked Pi pigs had significantly higher average daily gains than SH and BB pigs (P < 0.05). The activity of the focal pens was not influenced by the sire breed or tail lesion class, which might be due to the limited sample size of eight pens. To conclude, the use of the traditional sire breed BB has the potential to reduce injurious behaviour in the offspring. However, adjustments to the housing and feeding should be taken to further reduce the incidence of tail lesions and losses and to enhance performance.     

Source of amino acids for tRNA acylation in growing chicks

Summary Specific radioactivity in three amino acid compartments was examined in broiler chicks following a flooding dose of leucine or phenylalanine. In general, specific radioactivity of leucine and phenylalanine in deproteinated plasma (SA_e) and tissue (SA_i) compartments, exceeded that in acylated-tRNA (SA_t). In most tissues, SA_e and SA_i rapidly reached a similar peak level by 5 min followed by a slow decline for the next 30 minutes. Many tissues (eg. GI tract, liver, skin, and thigh) failed to maintain equilibrium between SA_e and SA_i over time. More metabolically active tissues, such as GI and liver had the greatest differences between these compartments. The difference between SA_e and SA_i for both leucine and phenylalanine were due to SA_i decreasing faster than SA_e, indicating dilution with unlabelled amino acids from proteolysis. Plasma and tissue specific radioactivity overestimated tRNA specific radioactivity by as much as 5 and 2.8 fold using leucine or 2.7 and 1.4 fold using phenylalanine, respectively. These data suggest that intracellular compartmentation of protein metabolism and the coupling of protein degradation and synthesis occur, in vivo.     

盐度对凡纳滨对虾体组织蛋白质积累、氨基酸组成和转氨酶活性的影响

本文研究了低、中和高三个盐度水平(分别为3‰、17‰和32‰)对凡纳滨对虾(Litopenaeus vannamei)各组织蛋白质的积累、肌肉谷草转氨酶和谷丙转氨酶活力、肌肉总氨基酸和游离氨基酸组成和含量的影响。结果显示,经过50d不同盐度水平的试验,低盐度组对虾的肝胰腺和血淋巴中可溶性蛋白质含量显著高于中、高盐度组(p<0.05),而肌肉中可溶性蛋白质含量在各处理组间无显著性差异;低、高盐度均导致肌肉中谷丙转氨酶和谷草转氨酶活力升高,但是各处理间的差异不显著;低、高盐度组凡纳滨对虾肌肉总氨基酸和总必需氨基酸含量均显著高于中盐度组(p<0.05),中、低盐度处理组非必需氨基酸含量差异不显著,而低盐度组对虾肌肉中蛋氨酸、丝氨酸、半胱氨酸和脯氨酸含量均显著低于中盐度组(p<0.05),其中脯氨酸为常见的5种主要渗透调节氨基酸之一;低、高盐度组对虾肌肉总游离氨基酸含量显著高于中盐度组(p<0.05),而盐度对机体绝大部分肌肉游离氨基酸含量的影响不显著(p>0.05)。结果显示,当环境盐度偏离凡纳滨对虾最适生长盐度时,其可通过在肝胰腺和血淋巴蛋白质积累及提高自身转氨酶活力,来获得机体在渗透调节供能时所需的氨基酸,而这些氨基酸以脯氨酸为主。     

Use of fuzzy clustering technique and matrices to classify amino acids and its impact to Chou's pseudo amino acid composition

In this paper we present a study of classification of the 20 amino acids via a fuzzy clustering technique. In order to calculate distances among the various elements we employ two different distance functions: the Minkowski distance function and the NTV metric. In the clustering procedure we take into account several physical properties of the amino acids. We examine the effect of the number and nature of properties taken into account to the clustering procedure as a function of the degree of similarity and the distance function used. It turns out that one should use the properties that determine in the more important way the behavior of the amino acids and that the use of the appropriate metric can help in defining the separation into groups.     

Protein metabolism,body composition and oxygen consumption in young bulls divergent in residual feed intake offered two contrasting forage-based diets

Protein metabolism and body composition have been identified as major determinants of residual feed intake (RFI) in beef cattle fed high-starch fattening diets. This study aimed to evaluate if these two identified RFI determinants in beef cattle are the same across two contrasting silage-based diets. During two consecutive years, an 84-day feed efficiency test (Test A) immediately followed by a second 112-day feed efficiency test (Test B) was carried out using a total of 100 animals offered either one of two diets (either corn silage- or grass silage-based) over 196 days. At the end of Test A, the 32 animals most divergent for RFI (16 extreme RFI animals per diet, eight low RFI and eight high RFI) were identified and evaluated during Test B for their i) N use efficiency (NUE; N retention/N intake) calculated either from a 10-d nitrogen balance trial or from estimations based on body composition changes occurring during the whole experiment (Test A and Test B; 196 days), ii) carcass and whole-body protein turnover rates analysed through the 3-methyl-histidine urinary excretion and the N isotopic turnover rates of urine, respectively, and iii) body composition measured at the slaughterhouse at the end of Test B. Oxygen consumption was measured during Test B for the 100 animals by two GreenFeed systems. Irrespective of the diet, efficient RFI animals tended (P = 0.08) to improve their NUE when N retention was estimated for 196 days or when considering their lower urinary urea-N to total N ratio (P = 0.03). In contrast, NUE calculated during the 10-d N balance showed no differences (P = 0.65) across RFI groups suggesting that this method may not be suitable to capture small NUE differences. Efficient RFI individuals presented higher dressing percentage and muscle deposition in the carcass (P = 0.003) but lighter rumen (P = 0.001), and a trend for lower oxygen consumption (P = 0.08) than inefficient RFI animals irrespective of the diet. Lower protein degradation rates of skeletal muscle and lower protein synthesis rates of plasma proteins were found in efficient RFI cattle but only with the corn silage-based diet (RFI × Diet; P = 0.02). The higher insulinaemia associated with the corn silage-based diet (P = 0.001) seemed to be a key metabolic feature explaining the positive association between protein turnover and RFI only in this diet. Feed N was more efficiently used for growth by efficient RFI animals regardless of the diet but lower protein turnover rates in efficient RFI animals were only observed with corn silage-based diets.     

Growth rates of contract-reared versus home-reared replacement dairy heifers

Successful heifer rearing is dependent on achieving optimal average daily gain (ADG) targets to calve for the first time at 24 months. Whilst dairy farmers internationally have traditionally managed their heifers on-farm to achieve these targets, recent dairy herd expansion within Europe has resulted in increased demand for labour-saving heifer-rearing strategies, such as off-farm contractrearing. However, loss of direct influence on the day-to-day management decisions affecting the ability of heifers to grow adequately to achieve this age of first calving may represent a potential barrier to uptake. Hence, the aim of this longitudinal observational study was to compare the growth rates of contract- vs home-reared heifers. Approximately 6 500 heifers from 120 commercial Irish dairy farms were enrolled in a 3-year study. For 65 of these farms, heifers were reared at a contract-rearing facility. For the remaining 55 farms, heifers were reared on their home farm. Over the course of 20 months from birth until precalving, heifers were examined and weighed at four farm visits. The relationship between several independent variables (farm type, herd size, heifer breed, economic breeding index (EBI) and health events) and ADG at different time points was investigated and analysed utilising linear mixed models. Overall ADG for heifers throughout the rearing period was 0.71 kg/day. There was a significant association between farm type and ADG for all five linear ADG models; home-reared heifers grew, on average, 0.025, 0.039, 0.11 and 0.059 kg/day more than contract-reared heifers between visit 1 and visit 4 (overall ADG), visit 1 and visit 2, visit 2 and visit 3 and visit 1 and visit 3, respectively. The occurrence of diarrhoea during farm visit 2 (median age 8.5 months) was associated with a significant reduction in ADG between visit 3 and visit 4. Calf-hood disease (diarrhoea, respiratory disease or navel ill) was not associated with the growth rate during any of the subsequent visit periods. While home-reared heifers had greater ADG during four of the five periods studied, median heifer ADG in both cohorts exceeded the minimum published target weight gains at each developmental stage required for heifers to reach puberty, conceive at 15 months and calve for the first time at 24 months. Importantly, there was wide variation both within enterprises and between farms. It was concluded that while the absolute difference in daily growth rates of home- and contract-reared heifers was minimal, when considered in the context of the entire heifer-rearing period, these growth rate differences have the potential to impact the future reproductive and milk production performance of heifers.     

Site specificity of protein glycation

Summary The rate of nonenzymatic glycation of a protein amino group is dependent upon a number of factors, such as the accessibility to glucose molecules in solution, and local acid-base catalysis of the rearrangement of the Schiff base that is formed initially. This is illustrated by a study of the site specificity of liver alcohol dehydrogenase, in which an attempt has been made to interpret the data in terms of the three-dimensional structure of the enzyme molecule.