Effects of Different Protein Energy Ratios on Fattening Performance,Slaughter Performance and Meat Quality of Pigs

[Objectives]Protein energy ratio refers to the proportional relationship between protein and energy levels in animal diets,i.e.,the grams of crude protein corresponding to every megacalorie of energy,which is generally expressed as CP:ME or CP:DE.This study was conducted to investigate the effects of different diets on fattening and slaughter performance and meat quality traits for"L(Large Yorkshire)×L(Landrace)"crossbred pigs.[Methods]Eighteen piglets of L×L crossbred with similar body weights about 51 kg were selected.The piglets were divided into 3 groups randomly and each group was assigned to 3 replicates with 2 piglets in a replicate.Group A was fed diet Ⅰ (control diet),group B was fed the same diet of group A in the first month of the trial but fed diet Ⅱ in second month,and group C consumed diet Ⅲ.All the pigs were fed in the same feeding condition for two months except the different diets during the trial.One pig in similar body weight from each replicate was slaughtered for the determination of slaughter performance and meat quality traits in the end of the trial.[Results]The average daily feed intake(ADFI)of pigs from group B was only(2.32±0.52)kg and significantly lower than those from group A and group C(P<0.05),but no difference was found in average daily gain(ADG) and feed/gain(P>0.05).Also,no differences occurred in the carcass length,back fat thickness,longissimus muscle (LM) area and dressing percentage(P>0.05).In addition,no differences were found in the meat quality traits of shear force,meat color,pH_(45 min),pH_(24 h) and cooking loss(P>0.05).However,the water-holding capacity of meat from group C was(2.58±0.02)ms and significantly lower than that of(2.80±0.20)ms from group A(P<0.05).Although the contents of glutamic acid and cystine in LM from group B was significantly lower than those from group A and group C(P<0.05),no differences occurred in the contents of other amino acids,the total amino acid and total flavor amino acid among the three groups(P>0.05).However,the inosine monophosphate content of LM from group C was only(331.80±11.53)mg/100 g and significantly lower than those of(361.00±6.36)and(366.37±4.80)mg/100 g from group A and B(P<0.05).Even though no differences were found in the contents of DM and CP in LM among the three groups of pigs,the content of intramuscular fat(IMF)in LM from group B and group C was increased by 45.6%and 46.58%respectively from that of group A(P<0.05),but no difference occurred between group B and C(P>0.05).[Conclusions]DietsⅡ and Ⅲ in this study caused no differences in fattening and slaughter performance of L×L crossbred pigs,but the effects on some meat traits were still significant,especially on the improvement of intramuscular fat in experimental pigs.Therefore,they could improve the meat quality of crossbred pigs to a certain extent.

Effects of dietary protein/energy ratio on growth performance,carcass trait,meat quality,and plasma metabolites in pigs of different genotypes

Background： The protein/energy ratio is important for the production performance and utilization of available feed resources by animals. Increased protein consumption by mammals leads to elevated feed costs and increased nitrogen release into the environment. This study aimed to evaluate the effects of dietary protein/energy ratio on the growth performance, carcass traits, meat quality, and plasma metabolites of pigs of different genotypes. Methods： Bama mini-pigs and Landrace pigs were randomly assigned to two dietary treatment groups （Chinese conventional diet with low protein/energy ratio or National Research Council diet with high protein/energy ratio; n = 24 per treatment） in a 2 x 2 factorial arrangement. Blood and muscle samples were collected at the end of the nursery, growing, and finishing phases. Results： We observed significant interactions （P 〈 0.05） between breed and diet for total fat percentage, intramuscular fat （IMF） content, protein content in biceps femoris （BF） muscle, and plasma urea nitrogen （UN） concentration in the nursery phase; for average daily gain （ADG）, average daily feed intake （ADFI）, dry matter, IMF content in psoas major （PM） muscle, and plasma total protein and albumin concentrations in the growing phase; and for drip loss and plasma UN concentration in the finishing phase. Breed influenced （P 〈 0.05） growth performance, carcass traits, and meat quality, but not plasma metabolites. Throughout the trial, Landrace pigs showed significantly higher （P 〈 0.0_5） ADG, ADFI, dressing percentage, lean mass rate, and loin-eye area than did Bama mini-pigs, but significantly lower （P 〈 0.0.5） feed/gain ratio, fat percentage, backfat thickness, and IMF content. Dietary protein/energy ratio influenced the pH value, chemical composition of BF and PM muscles, and plasma activities of glutamic-pyruvic transaminase and gamma-glutamyl transpeptidase, and plasma concentration of UN. Conclusions： Compared with Landrace pigs, Bama mini-pigs showed slower growth and lower carcass performance, but had better meat quality. Moreover, unlike Landrace pigs, the dietary protein/energy ratio did not affect the growth performance of Bama mini-pigs. These results suggest that, in swine production, low dietary protein/energy ratio may be useful for reducing feed costs and minimizing the adverse effects of ammonia release into the environment.

Effects of dietary protein restriction on muscle fiber characteristics and m TORC1 pathway in the skeletal muscle of growing-finishing pigs

Background： To investigate the effects of dietary crude protein（CP） restriction on muscle fiber characteristics and key regulators related to protein deposition in skeletal muscle, a total of 18 growing-finishing pigs（62.30 ± 0.88 kg）were allotted to 3 groups and fed with the recommended adequate protein（AP, 16 % CP） diet, moderately restricted protein（MP, 13 % CP） diet and low protein（LP, 10 % CP） diet, respectively. The skeletal muscle of different locations in pigs, including longissimus dorsi muscle（LDM）, psoas major muscle（PMM） and biceps femoris muscle（BFM） were collected and analyzed.Results： Results showed that growing-finishing pigs fed the MP or AP diet improved（P 〈 0.01） the average daily gain and feed： gain ratio compared with those fed the LP diet, and the MP diet tended to increase（P = 0.09） the weight of LDM. Moreover, the ATP content and energy charge value were varied among muscle samples from different locations of pigs fed the reduced protein diets. We also observed that pigs fed the MP diet up-regulated（P 〈 0.05） muscular m RNA expression of all the selected key genes, except that myosin heavy chain（My HC） IIb,My HC IIx, while m RNA expression of ubiquitin ligases genes was not affected by dietary CP level. Additionally, the activation of mammalian target of rapamycin complex 1（m TORC1） pathway was stimulated（P 〈 0.05） in skeletal muscle of the pigs fed the MP or AP diet compared with those fed the LP diet.Conclusion： The results suggest that the pigs fed the MP diet could catch up to the growth performance and the LDM weight of the pigs fed the AP diet, and the underlying mechanism may be partly due to the alteration in energy status, modulation of muscle fiber characteristics and m TORC1 activation as well as its downstream effectors in skeletal muscle of different locations in growing-finishing pigs.

Dietary lipid and gross energy affect protein utilization in the rare minnow Gobiocypris rarus

An 8-week feeding trial was conducted to detect the optimal dietary protein and energy, as well as the ef fects of protein to energy ratio on growth, for the rare minnow( Gobiocypris rarus), which are critical to nutrition standardization for model fi sh. Twenty-four diets were formulated to contain three gross energy(10, 12.5, 15 kJ/g), four protein(20%, 25%, 30%, 35%), and two lipid levels(3%, 6%). The results showed that optimal dietary E/P was 41.7–50 kJ/g for maximum growth in juvenile rare minnows at 6% dietary crude lipid. At 3% dietary lipid, specifi c growth rate(SGR) increased markedly when E/P decreased from 62.5 kJ/g to 35.7 kJ/g and gross energy was 12.5 kJ/g, and from 75 kJ/g to 42.9 kJ/g when gross energy was 15.0 kJ/g. The optimal gross energy was estimated at 12.5 kJ /g and excess energy decreased food intake and growth. Dietary lipid exhibited an apparent protein-sparing eff ect. Optimal protein decreased from 35% to 25%–30% with an increase in dietary lipid from 3% to 6% without adversely ef fecting growth. Dietary lipid level af fects the optimal dietary E/P ratio. In conclusion, recommended dietary protein and energy for rare minnow are 20%–35% and 10–12.5 k J/g, respectively.

Metabolomic changes in fatty liver can be modified by dietary protein and calcium during energy restriction

AIM： To characterise the effect of energy restriction （ER） on liver lipid and primary metabolite profile by using metabolomic approach. We also investigated whether the effect of energy restriction can be further enhanced by modification of dietary protein source and calcium. METHODS： Liver metabolomic profile of lean and obese C57BI/6J mice （n = 10/group） were compared with two groups of weight-reduced mice. ER was performed on control diet and whey protein-based high-calcium diet （whey ＋ Ca）. The metabolomic analyses were performed using the UPLC/MS based lipidomic platform and the HPLC/MS/MS based primary metabolite platform.RESULTS： ER on both diets significantly reduced hepatic lipid accumulation and lipid droplet size, while only whey ＋ Ca diet significantly decreased blood glucose （P 〈 0.001） and serum insulin （P 〈 0.01）. In hepatic lipid species the biggest reduction was in the level of triacylglycerols and cerarnides while the level of cholesterol esters was significantly increased during ER. Interestingly, diacylglycerol to phospholipid ratio, an indicator of relative amount of diabetogenic diglyceride species, was increased in the control ER group, but decreased in the whey ＋ Ca ER group （P 〈 0.001, vs obese）. ER on whey ＋ Ca diet also totally reversed the obesity induced increase in the relative level of lipotoxic cerarnides （P 〈 0.001, vs obese; P 〉 0.05, vs lean）. These changes were accompanied with up-regulated TCA cycle and pentose phosphate pathway rnetabolites. CONCLUSION： ER-induced changes on hepatic rnetabolornic profile can be significantly affected by dietary protein source. The therapeutic potential of whey protein and calcium should be further studied.

能谱CT定量参数联合NLR、CAR检测对非小细胞肺癌根治术后复发转移的预测价值

目的:探讨能谱CT定量参数联合NLR、CAR检测对非小细胞肺癌(NSCLC)根治术后复发转移的预测价值。方法:选择2018年1月至2021年6月于我院就诊并接受根治性切除术的114例NSCLC患者作为研究对象,术前对患者行胸部平扫及双期增强扫描,记录平扫有效原子序数(Eff-Z)、病灶处动脉期标准化碘浓度(NICVP)和静脉期标准化碘浓度(NICAP)、碘浓度差值(ICD)。术前采用全自动血细胞分析仪检测中性粒细胞、淋巴细胞计数,采用免疫比浊法测定血清C反应蛋白水平,溴甲酚绿法测定血清白蛋白水平,计算并记录中性粒细胞/淋巴细胞比值(NLR)、C反应蛋白水平/白蛋白比值(CAR)。患者术后门诊随访2年,观察是否发生复发转移。结果:术后复发转移与未复发转移NSCLC患者的性别、年龄、BMI、家族肿瘤史、吸烟史和病理类型比较差异均无统计学意义(P均>0.05);术后复发转移组患者中临床分期为Ⅱ期和有淋巴结转移的比例显著高于术后无复发转移组(P<0.05)。术后复发转移患者的Eff-Z、NICVP、NICAP、ICD均低于未复发转移组(P<0.05),NLR、CAR均高于未复发转移组(P<0.05)。多因素Logistic回归分析结果显示,TNM分期、淋巴结转移、Eff-Z、NICAP、NLR、CAR水平是NSCLC患者术后复发转移的独立影响因素(P<0.05)。建立Logistic回归方程如下:Logit(P)=-0.179+1.211×TNM分期+1.161×淋巴结转移+(-0.209)×Eff-Z+(-0.368)×NICAP+0.842×NLR+0.934×CAR。ROC曲线分析结果显示,建立的模型预测NSCLC患者术后复发转移的曲线下面积为0.958(95%CI:0.920~0.997,P<0.001),敏感度和特异度分别为92.0%和85.4%,优于各指标的单独预测效能。结论:联合应用临床病理特征、能谱CT定量参数及NLR、CAR检测对非小细胞肺癌根治术后复发转移的预测效能较好,具有一定临床应用价值。

外周血Adropin、IL⁃6、NLR对急性脑出血患者预后的预测价

目的探究外周血Adropin蛋白、白细胞介素6(IL⁃6)、中性粒细胞与淋巴细胞比值(NLR)对急性脑出血患者预后的预测价值。方法分析82例南通市海门区人民医院2018年9月至2023年9月期间救治的急性脑出血患者资料,治疗后进行3个月随访,采用改良Rankin量表评估预后并将患者分为预后良好组(n=49)和预后不良组(n=33)。比较两组入院时临床检查、影像学及实验室指标等基线资料,分析急性脑出血患者近期预后的影响因素,绘制受试者工作特征(ROC)曲线评价外周血Adropin、IL⁃6、NLR水平对脑出血患者预后的预测价值。结果相比预后良好组,预后不良组患者合并高血压占比、合并糖尿病占比、饮酒者占比、出血破入脑室者占比、年龄、入院时NIHSS评分、出血量以及外周血IL⁃6、NLR水平更高,差异均具有统计学意义(χ ^(2)=5.722、9.175、4.192、4.058,t=3.456、6.907、3.377、6.760、6.165,P<0.05);预后不良组患者外周血Adropin水平则低于预后良好组(t=6.430,P<0.05);多因素Logistic回归分析结果显示急性脑出血患者年龄、入院时NIHSS评分、外周血Adropin水平降低、IL⁃6及NLR水平升高是其预后不良的独立危险因素(P<0.05);ROC曲线结果显示外周血Adropin、IL⁃6、NLR联合预测患者预后不良的曲线下面积为0.943,优于单一检测(P<0.05)。结论外周血Adropin、IL⁃6、NLR对急性脑出血患者预后有一定预测价值,三者联合检测预测效能更高。

NLR、PLR、Lp-PLA2对维持性血液透析患者蛋白质能量消耗的联合诊断价值

目的探讨中性粒细胞与淋巴细胞比值(neutrophil/lymphocyte ratio,NLR)、血小板与淋巴细胞比值(platelet/lymphocyte ratio,PLR)、脂蛋白相关磷脂酶A2(lipoprotein phospholipase A2,Lp-PLA2)在维持性血液透析(maintenance hemodialysis,MHD)患者蛋白质能量消耗(protein energy wasting,PEW)的联合诊断价值。方法收集泰州市人民医院327例接受MHD治疗患者临床资料,根据国际肾脏营养和代谢学会(international society of renal nutrition and metabolism,ISRNM)诊断标准,将MHD患者分为PEW组和非PEW组。探索NLR、PLR、Lp-PLA2在MHD患者PEW诊断中的应用价值。结果327例患者中有101例患者发生PEW,发生率为31%。PEW组患者体质量指数(body mass index,BMI)、白蛋白、前白蛋白、总胆固醇、肌酐、尿酸水平均低于非PEW组患者(Z/t=-5.358、-8.147、-5.363、-2.297、-4.168、-2.326,P<0.001、<0.001、<0.001、0.022、<0.001、0.020),年龄、NLR、PLR、Lp-PLA2水平均高于非PEW组(Z/t=-2.753、-5.588、-4.672、-9.269,P=0.006、<0.001、<0.001、<0.001)。多因素二元Logistic逐步回归方程分析结果显示NLR(OR=1.094,95%CI:1.004~1.192,P=0.041)、PLR(OR=1.021,95%CI:1.009~1.033,P<0.001)、Lp-PLA2(OR=1.085,95%CI:1.056~1.114,P<0.001)水平是血液透析患者发生PEW的独立风险因子。NLR(95%CI:0.631~0.756,P<0.001)、PLR(95%CI:0.597~0.726,P<0.001)、Lp-PLA2(95%CI:0.735~0.841,P<0.001)、NLR联合PLR(95%CI:0.650~0.775,P<0.001)、NLR联合Lp-PLA2(95%CI:0.800~0.889,P<0.001)、PLR联合Lp-PLA2(95%CI:0.782~0.875,P<0.001)、NLR联合PLR及Lp-PLA2(95%CI:0.809~0.895,P<0.001)在ROC曲线下面积分别为0.693、0.662、0.788、0.713、0.844、0.829、0.852,NLR、PLR、Lp-PLA2均对MHD患者发生PEW具有一定的诊断价值,且当三者联合时ROC曲线下面积为0.852(95%CI:0.809~0.895,P<0.001),诊断效能最大。结论NLR、PLR、Lp-PLA2水平可作为MHD患者发生PEW的参考指标,加强对NLR、PLR、Lp-PLA2水平的联合监测可为PEW的诊断及治疗提供干预证据。

Relationship between high dietary fat intake and Parkinson’s disease risk: a meta-analysis

OBJECTIVE: To assess whether dietary fat intake influences Parkinson’s disease risk. DATA SOURCES: We systematically surveyed the Embase and PubMed databases, reviewing manuscripts published prior to October 2018. The following terms were used:(“Paralysis agitans” OR “Parkinson disease” OR “Parkinson” OR “Parkinson’s” OR “Parkinson’s disease”) AND (“fat” OR “dietary fat” OR “dietary fat intake”). DATA SELECTION: Included studies were those with both dietary fat intake and Parkinson’s disease risk as exposure factors. The Newcastle-Ottawa Scale was adapted to investigate the quality of included studies. Stata V12.0 software was used for statistical analysis. OUTCOME MEASURES: The primary outcomes included the relationship between high total energy intake, high total fat intake, and Parkinson’s disease risk. The secondary outcomes included the relationship between different kinds of fatty acids and Parkinson’s disease risk. RESULTS: Nine articles met the inclusion criteria and were incorporated into this meta-analysis. Four studies scored 7 and the other five studies scored 9 on the Newcastle-Ottawa Scale, meaning that all studies were of high quality. Meta-analysis results showed that high total energy intake was associated with an increased risk of Parkinson’s disease (P = 0.000, odds ratio (OR)= 1.49, 95% confidence interval (CI): 1.26–1.75);in contrast, high total fat intake was not associated with Parkinson’s disease risk (P = 0.123, OR = 1.07, 95% CI: 0.91–1.25). Subgroup analysis revealed that polyunsaturated fatty acid intake (P = 0.010, OR = 1.03, 95% CI: 0.88–1.20) reduced the risk of Parkinson’s disease, while arachidonic acid (P = 0.026, OR = 1.15, 95% CI: 0.97–1.37) and cholesterol (P = 0.002, OR = 1.09, 95% CI: 0.92–1.29) both increased the risk of Parkinson’s disease. Subgroup analysis also demonstrated that, although the results were not significant, consumption of n-3 polyunsaturated fatty acids (P = 0.071, OR = 0.88, 95% CI: 0.73–1.05),α-linolenic acid (P = 0.06, OR = 0.86, 95% CI: 0.72–1.02), and the n-3 to n-6 ratio (P = 0.458, OR = 0.89, 95% CI: 0.75–1.06) were all linked with a trend toward reduced Parkinson’s disease risk. Monounsaturated fatty acid (P = 0.450, OR = 1.06, 95% CI: 0.91–1.23), n-6 polyunsaturated fatty acids (P = 0.100, OR = 1.15, 95% CI: 0.96–1.36) and linoleic acid (P = 0.053, OR = 1.11, 95% CI: 0.94–1.32) intakes were associated with a non-significant trend toward higher PD risk. Saturated fatty acid (P = 0.619, OR = 1.01, 95% CI: 0.87–1.18) intake was not associated with Parkinson’s disease. CONCLUSION: Dietary fat intake affects Parkinson’s disease risk, although this depends on the fatty acid subtype. Higher intake of polyunsaturated fatty acids may reduce the risk of Parkinson’s disease, while higher cholesterol and arachidonic acid intakes may elevate Parkinson’s disease risk. However, further studies and evidence are needed to validate any link between dietary fat intake and Parkinson’s disease.

饲粮能氮比对简州大耳羊粪便排泄参数及微生物区系的影响

为探索全价颗粒饲粮不同能氮比对全舍饲简州大耳羊粪便排泄参数、氮排泄参数以及粪便微生物区系的影响,选择32只(公母各半)(26.16±2.39)kg的6月龄健康简州大耳羊,随机分到a、b、c、d组,分别饲喂能氮比为0.59、0.51、0.43、0.35的全价颗粒饲粮,开展12 d全收粪尿试验,并采集新鲜直肠粪便测定微生物区系。结果表明:降低饲粮能氮比对试验羊干物质采食量、粪便及尿液排泄参数、氮排泄率和粪氮排泄量均无显著影响,但粪便pH、尿总氮、尿氨氮、日排总氮、单位代谢体质量尿氮和总氮的日排泄量均呈线性增加。随着饲粮能氮比降低,a、b、c组粪便微生物区系无显著差异,但d组Shannon指数和Simpson指数降低;在门水平上,d组厚壁菌门的相对丰度降低,疣微菌门和放线菌门的相对丰度提高;在细菌属水平上,艾克曼菌属的相对丰度提高。综上所述,降低全价颗粒饲粮能氮比将提高简州大耳粪便pH、增加尿氮的排泄,而且能氮比过低(0.35)会影响粪便微生物区系,进而影响机体健康。

糖尿病肾病血液透析患者发生蛋白质能量消耗的影响因素

目的 观察糖尿病肾病(DN)血液透析患者蛋白质能量消耗(PEW)发生状况,并分析其发生的影响因素。方法 选择2019年1月至2021年5月在商丘市第六人民医院接受血液透析治疗的110例DN患者作为研究对象,所有患者均规律治疗6个月,统计DN血液透析患者治疗期间PEW的发生状况,并设计一般人口资料表,分析DN血液透析患者PEW发生的影响因素。结果 血液透析治疗期间,110例DN患者中57例发生PEW,发生率为51.82%;发生组血压、贫血、服用维生素、水分比、血清C反应蛋白(CRP)水平与未发生组比较,差异有统计学意义(P<0.05);经多因素logistic回归模型分析,结果显示,血压过高、贫血、未服用维生素、水分比高、血清CRP水平高是DN血液透析患者PEW发生的危险因素(OR>1,P<0.05)。结论 DN血液透析患者发生PEW的风险较高,其中血压过高、贫血、未服用维生素、水分比高、血清CRP水平高可能是导致DN血液透析患者发生PEW的影响因素。

不同能量蛋白比饲料对牙鲆体内消化酶活性的影响

采用9种不同能量蛋白比的饲料投喂牙鲆鱼苗,分析比较不同营养水平的饲料对牙鲆体内消化酶活性的影响.结果表明:随着饲料中能量蛋白比的增加,牙鲆胃肠道脂肪酶活性呈现出增强的趋势.在饲料中同一淀粉水平下,不同能量蛋白比的变化,未引起肠道淀粉酶活性呈现规律性变化.在饲料中同一蛋白水平下,能量蛋白比的变化,并未引起肠蛋白酶活性呈现规律性的变化,但是对饲料中蛋白水平在46%～52%,胃蛋白酶活性有随着能量蛋白比的升高而增强的趋势.牙鲆幼鱼饲料以蛋白水平在46%、能量蛋白比在31.72～36.81 kJ/g范围内,胃、肠道的蛋白酶、淀粉酶、脂肪酶活性较强.

翘嘴红鲌对饲料蛋白的营养需求及豆粕对鱼粉的适宜替代量

选择健康的翘嘴红鲌（Erythroculter ilishaeformis Bleeker）为实验鱼，体质量（12．84±0．60）g。实验分为两部分进行。实验Ⅰ以褐鱼粉为蛋白源，配制5个蛋白水平（31．04％、35．51％、40．89％、46．62％、50．33％）的等能、等必需氨基酸（EAA）平衡关联度的半精制饲料，探讨翘嘴红的对饲料蛋白的需求；经过8周饲养，实验Ⅰ的结果表明，饲料蛋白含量对翘嘴红鲌的增承率、饲料效率和蛋白效率具有显著影响。方差分析表明，40.89％饲料蛋白组的鱼体增重率显著高于31．04％、35．51％饲料蛋白组（P〈0．05），但是与46．62％和50．33％饲料蛋白组没有显著性差异（P〉0．05）；31．04％、35．51％和40．89％饲料蛋白组的蛋白效率显著高于46．62％和50．33％饲料蛋白组（P〈0．05）；40．89％、46．62％和50．33％饲料蛋白组的饲料效率显著高于31．04％和35．51％饲料蛋白组（P〈0．05）。依据折线模型分析翘嘴红鲌的增重率、二次多项式回归分析蛋白质效率，适宜饲料蛋白水平为37．43％～41．15％。实验Ⅱ以豆粕替代鱼粉，大豆蛋白分别替代0．0％、13．5％、27％、40．5％和54％的鱼粉蛋白，配制5个EAA关联度的等蛋白（40％）、等能（20MJ·kg^-1）的半精制饲料，探讨翘嘴红鲌饲料中大豆蛋白对鱼粉蛋白的适宜替代量。结果表明，当大豆蛋白分别替代13．5％、27．0％和40．5％的鱼粉蛋白时，翘嘴红鲌的增重率和蛋白效率与对照组差异不显著（P〉0．05），而且都显著高于54．0％替代组（P〈0．05），因此，本实验条件下，大豆蛋白对鱼粉蛋白的最大替代量为40．5％，饲料动、植物蛋白适宜比为3：2。

日粮能量和蛋白水平对桂香雏鸡饲料营养物质表观消化率的影响

【目的】明确桂香雏鸡日粮的适宜能量和粗蛋白需要量,为其饲养标准的制定提供理论依据。【方法】以1日龄桂香母鸡为研究对象,采用2因素3水平设计,设3个能量水平（11.57、12.17和12.77 MJ/kg）和3个粗蛋白质水平（17.5%,19.0%和20.5%）,探讨不同日粮能量和粗蛋白水平对桂香雏鸡阶段（1-4周龄）营养物质表观消化率的影响。【结果】日粮能量水平增加可有效提高桂香雏鸡的能量、粗蛋白、粗脂肪表观消化率,粗纤维表观消化率总体上也随日粮能量水平的提高而提高,钙、磷表观消化率的总体趋势呈先升后降,以中等能量水平下的表观消化率较高。随日粮蛋白水平的增加,除了显著降低粗蛋白消化率（P〈0.05,下同）及显著提高粗纤维消化率外,对其他营养物质表观消化率的影响均不显著（P〉0.05）。【结论】日粮能量和蛋白水平对桂香雏鸡饲料营养物质表观消化率有一定影响,实际生产中可选用能量和蛋白水平分别为12.77 MJ/kg和20.5%的日粮作为桂香雏鸡的主饲料。

大菱鲆幼鱼的蛋白质与能量需求

饲料中蛋白质的含量对大菱鲆幼鱼的生长起着决定性作用,适宜的能蛋比,既有利于能量的利用,又有利于蛋白质的利用,提高了饲料的利用率。设计4个蛋白质含量梯度和4个能量梯度的16组饲料,试验证明,蛋白质含量大于42％、能蛋比小于115,鱼体日增重率明显增大,饲料系数明显降低,表现出较高的饲料效率,本研究认为大菱鲆幼鱼配合饲料适宜的蛋白质含量为42％～45％、适宜的能蛋比为92.7～102.5。

鲻配合饲料适宜蛋白含量及蛋白能量比的初步研究

配制粗蛋白含量分别为24％、28％和32％的三种试验饲料投喂鲻共8周。结果表明蛋白含量为28％的饲料组的平均增重（克／尾）和特定生长率（％／d）均为最大值，饲料蛋白质含量对鲻肌肉成份没有影响。配制四种蛋白能量比（P：E）分别为86．2、90．3、94．9和100．0mg／kCal的饲料投喂鲻，养殖时间为6周。平均增量分别为32．5、34．2、31．3和23．8，特定生长率分别为0．70、0．79、0．74和0．60。随着P：E值的增大，肌肉成份没有明显的差异，但全鱼的蛋白含量升高而脂肪含量降低。根据增重率和鱼体腹腔脂肪储存量等指标，认为鲻配合饲料的适宜蛋白能量比为91mg／kCal。

翘嘴红鲌幼鱼最适蛋白需求量的研究

以鱼粉为蛋白源,配制5个不同蛋白水平的等能、等氨基酸平衡模式的半纯合饲料,饲养翘嘴红鱼白幼鱼2个月,探讨蛋白质的最适需要量。结果表明:饲料蛋白质水平对鱼的增重率、蛋白效率均具有显著的影响(P<0 05),质量分数为42 76%的饲料组鱼体增重显著高于32 58%、37 64%饲料组(P<0 05),但与47 53%和52 49%饲料组没有显著差异(P>0 05)。蛋白效率在各组之间的差异与增重率在各组之间的变化相类似。翘嘴红鱼白幼鱼最大增重的适宜蛋白水平为43 19%～48 68%,蛋白效率最大的饲料蛋白质质量分数为42 50%,饲料蛋白质量分数为37 64%、42 76%、47 53%3个饲料组的蛋白效率差异不显著(P>0 05)。在本试验条件下,翘嘴红鱼白幼鱼的蛋白质最适需要量为42 50%～43 19%。

南方鲇的营养学研究:饲料的最适蛋白质含量

设计了 6个不同蛋白质水平 (39.9% ,43.7% ,46.8% ,51 .6% ,55.7% ,59.1 % )的等能饲料 ,采用室内循环水养殖系统 ,在水温为 2 7.5± 0 .2℃的条件下对南方鲇幼鱼进行了 43d的生长实验。结果显示 :随饲料蛋白质含量的升高 ,特殊体重生长率 (SGR)、饲料干物质转化率 (FCEdm)、蛋白质转化率 (FCEp)、能量转化率 (FCEe)和蛋白质效率 (PER)均产生了显著的差异 (P <0 .0 5) ;干物质摄食率 (RLdm)与饲料蛋白质含量负相关 (r=- 0 .62 ,P <0 .0 1 ) ;蛋白质摄食率 (RLp)与饲料蛋白质含量正相关 (r=0 .96,P <0 .0 1 ) ;能量摄食率 (RLe)不受饲料蛋白质含量的影响 (P >0 .0 5)。通过讨论提出南方鲇饲料的最适蛋白质含量为 47%～ 51 %。

中华倒刺鲃幼鱼饲料蛋白质需求量的研究

以白鱼粉为蛋白源,设计了6个不同蛋白质含量(20.49%、26.48%、34.20%、41.02%、49.94%和55.86%,分别表示为D1、D2、D3、D4、D5和D6)的等能饲料,采用室内循环水养殖系统,在水温为(27.5±0.5)℃的条件下对中华倒刺鲃幼鱼进行10周的养殖实验,探讨中华倒刺鲃幼鱼对饲料蛋白质的需求量。每个处理设4个重复,每个重复12尾鱼。结果显示:干物质摄食率(FRdm)随饲料蛋白质含量升高呈先降低然后稳定的趋势;蛋白质摄食率(FRp)与饲料蛋白质含量呈正相关关系(r=0.982,p<0.01)。干物质表观消化率随饲料蛋白质含量增加而降低,蛋白质消化率在各组间无显著差异。随饲料蛋白质含量由D1逐渐增加至D4,体重特定生长率(SGRw)、能量特定生长率(SGRe)和饲料效率(FE)均显著增高(p<0.05),而D4、D5和D6组间无显著差异,其中D4组的三个指标值均最高,分别为(0.97±0.04)%/d、(0.87±0.04)%/d、(68.96±3.00)%。蛋白质效率(PER)、蛋白质累积率(PPV)和能量累积率(EPV)在各饲料组间均存在显著差异。以SGRw、SGRe和FE为指标,采用折线模型分析表明,中华倒刺鲃幼鱼的最适饲料蛋白质含量为39.6%—42.2%。

不同蛋白质源饲粮对肉牛能氮代谢和甲烷排放的影响

本试验旨在研究不同蛋白质源饲粮对肉牛能氮代谢和甲烷排放的影响。试验选用3头健康状况良好,体重接近并装有永久性瘤胃瘘管的宣汉黄牛,采用3×3完全拉丁方设计。试验饲粮分别以豆粕、菜籽粕、棉籽粕为蛋白质源进行配制;试验分3期,每期20 d,其中预试期10 d,消化试验3 d,呼吸代谢试验7 d。结果表明:1)各试验组的总挥发性脂肪酸浓度差异不显著(P>0.05),豆粕组和菜籽粕组的乙酸浓度显著高于棉籽粕组(P<0.05),菜籽粕组和棉籽粕组的丙酸浓度显著高于豆粕组(P<0.05),3组丁酸浓度差异显著(P<0.05),各组乙酸/丙酸差异显著(P<0.05),为豆粕组>菜籽粕组>棉籽粕组;各组氨态氮含量差异显著(P<0.05),为豆粕组>棉籽粕组>菜籽粕组。2)豆粕组、棉籽粕组、菜籽粕组的采食氮、粪氮、可消化氮以及氮消化率差异都不显著(P>0.05);尿氮则是豆粕组和棉籽粕组显著高于菜籽粕组(P<0.05),沉积氮和氮利用率则是菜籽粕组显著高于豆粕组和棉籽粕组(P<0.05)。3)3组尿能差异显著(P<0.05),为豆粕组>棉籽粕组>菜籽粕组,豆粕组的增重净能、增重净能/总能、增重净能/消化能和增重净能/代谢能均显著低于菜籽粕组和棉籽粕组(P<0.05)。4)3组甲烷排放量、甲烷能和甲烷能/总能以及每千克干物质采食量的甲烷排放量差异均显著(P<0.05),均为豆粕组>菜籽粕组>棉籽粕组。综上所述,以菜籽粕为蛋白质源的饲粮氮生物学效价最高,豆粕次之,棉籽粕最低;以棉籽粕为蛋白质源的饲粮增重净能最高,菜籽粕次之,豆粕最低;以豆粕为蛋白质源的饲粮的甲烷排放量最高,菜籽粕次之,棉籽粕最低。