饲料蛋白质和能量水平对齐口裂腹鱼生长、体组成和蛋白质利用的影响

齐口裂腹鱼（Schizothorax prenanti Tchang）隶属鲤科、裂腹鱼亚科,俗称“雅鱼”,为长江上游重要经济鱼类,也是川西高原特有的冷水性鱼类。其肉质细嫩,味道鲜美,是名贵野生经济鱼类。近年来由于过度捕捞、环境污染等因素的影响,齐口裂腹鱼种群数量不断下降,分布区域日趋缩小,而随着人们生活水平的不断提高,对齐口裂腹鱼等名优水产品的需求却在不断增加。为保护和持续利用这一野生动物资源,     

Effects of genomic estimated breeding value and dietary energy to protein ratio on growth performance,carcass trait,and lipogenic gene expression in Hanwoo steer

“Genome-based precision feeding” is a concept that involves the application of customised diets to different genetic groups of cattle. We investigated the effects of the genomic estimated breeding value (gEBV) and dietary energy to protein ratio (DEP) on growth performance, carcass traits, and lipogenic gene expression in Hanwoo (Korean cattle) steers. Forty-four Hanwoo steers (BW = 636 kg, age = 26.9 months) were genotyped using the Illumina Bovine 50 K BeadChip. The gEBV was calculated using genomic best linear unbiased prediction. Animals were separated into high gEBV of marbling score or low-gMS groups based on the upper and lower 50% groupings of the reference population, respectively. Animals were assigned to one of four groups in a 2 × 2 factorial arrangement: high gMS/high DEP (0.084 MJ/g), high gMS/low DEP (0.079 MJ/g), low gMS/high DEP, and low gMS/low DEP. Steers were fed concentrate with a high or low DEP for 31 weeks. The BW tended to be higher (0.05 < P < 0.1) in the high-gMS groups compared to the low-gMS groups at 0, 4, 8, 12, and 20 weeks. The average daily gain (ADG) tended to be lower (P = 0.08) in the high-gMS group than in the low-gMS group. Final BW and measured carcass weight (CW) were positively correlated with the gEBV of carcass weight (gCW). The DEP did not affect ADG. Neither the gMS nor the DEP affected the MS and beef quality grade. The intramuscular fat (IMF) content in the longissimus thoracis (LT) tended to be higher (P = 0.08) in the high-gMS groups than in the low-gMS groups. The mRNA levels of lipogenic acetyl-CoA carboxylase and fatty acid binding protein 4 genes in the LT were higher (P < 0.05) in the high-gMS group than in the low-gMS group. Overall, the IMF content tended to be affected by the gMS, and the genetic potential (i.e., gMS) was associated with the functional activity of lipogenic gene expression. The gCW was associated with the measured BW and CW. The results demonstrated that the gMS and the gCW may be used as early prediction indexes for meat quality and growth potential of beef cattle.     

Short-term, increasing dietary protein and fat moderately affect energy expenditure, substrate oxidation and uncoupling protein gene expression in rats

Macronutrient composition of diets can influence body-weight development and energy balance. We studied the short-term effects of high-protein (HP) and/or high-fat (HF) diets on energy expenditure (EE) and uncoupling protein (UCP1-3) gene expression. Adult male rats were fed ad libitum with diets containing different protein-fat ratios: adequate protein-normal fat (AP-NF): 20% casein, 5% fat; adequate protein-high fat (AP-HF): 20% casein, 17% fat; high protein-normal fat (HP-NF): 60% casein, 5% fat; high protein-high fat (HP-HF): 60% casein, 17% fat. Wheat starch was used for adjustment of energy content. After 4 days, overnight EE and oxygen consumption, as measured by indirect calorimetry, were higher and body-weight gain was lower in rats fed with HP diets as compared with rats fed diets with adequate protein content (P<.05). Exchanging carbohydrates by protein increased fat oxidation in HF diet fed groups. The UCP1 mRNA expression in brown adipose tissue was not significantly different in HP diet fed groups as compared with AP diet fed groups. Expression of different homologues of UCPs positively correlated with nighttime oxygen consumption and EE. Moreover, dietary protein and fat distinctly influenced liver UCP2 and skeletal muscle UCP3 mRNA expressions. These findings demonstrated that a 4-day ad libitum high dietary protein exposure influences energy balance in rats. A function of UCPs in energy balance and dissipating food energy was suggested. Future experiments are focused on the regulation of UCP gene expression by dietary protein, which could be important for body-weight management.     

饲粮蛋白质水平对蜂群繁殖性能的影响

本试验旨在研究饲料蛋白质水平对蜜蜂产浆期繁殖性能的影响。选择35群群势、蜂王年龄和质量一致的意大利蜜蜂Apis mellifera L.,随机分为7组,分别饲喂蛋白质水平为15%、20%、25%、30%、35%及40%的试验饲粮并以油菜花粉作为对照,测定各组蜂群的繁殖性能。结果表明,试验前期,饲粮蛋白质水平对蜂群群势有显著性影响,然而在试验中后期,则无显著影响(P>0.05);随着饲粮蛋白质水平的增加,蜂王产卵力和工蜂初生重呈先升高后降低的变化趋势,与对照组相比差异不显著(P>0.05)。     

Effects of dietary soybean protein levels on energy budget of the southern catfish, Silurus meridionalis

Energy budgets were calculated for the southern catfish, Silurus meridionalis, fed diets replacing 0%, 13%, 26%, 39%, 52% and 65% fish meal protein with soybean meal (SBM) protein with or without methionine supplementation to apparent satiation at 27.5 degrees C. With increasing dietary soybean protein levels (SPL), the feed energy lost in feces, excretion and metabolism increased, while that available for growth decreased (P<0.05). When 0.12% or 0.26% methionine at 39% SPL was added to reach that in body carcass or the control group (0% SPL), no significant differences were found in each component of energy budgets. When 0.21% or 0.33% methionine at 52% SPL was added to reach the content of methionine in body carcass or the control group, energy spent on growth increased, but that on excretion and metabolism decreased (P<0.05). These results suggested that the differences in growth rate among the southern catfish fed the diets with different SPL were due to decreasing absorption rate, increasing excretion and metabolism with increasing dietary SPL. The most important factor limiting the use of soybean protein was the imbalance of essential amino acids, which resulted in more energy spent on metabolism and excretion, less energy on growth. Supplementation of methionine produced a relatively better amino acid profile and subsequently improved the utilization of soybean protein at high SPL, which resulted in less energy used for metabolism or lost in excretion and more energy available for growth.     

Effects of various energy and protein levels during sequential feeding on feed preferences in meat-type chickens

Short-term feed preferences were studied in individually caged chickens fed sequentially in order to understand a previously described imbalance in the intake of diets offered. Sequential feeding (SF) was carried out for four 48 h cycles in male broiler chickens. The diets varied in energy (2800 (E−) and 3200 kcal/kg (E+)) and protein (230 (P+) and 150 g/kg (P−)) contents. SF was compared to standard feeding (C) (3000 kcal/kg ME and CP = 190 g/kg). In experiment 1, three treatments were used: C, S_E (E− followed by E+) and S_E′ (E+ followed by E−). Four treatments were used in experiment 2: C, S_P (P+ followed by P−), S_E and S_EP (P+E− followed by P−E+). Total feed intake was measured during the SF period. After this, short-term preferences were evaluated with a choice test on chickens previously fed with the same feeds during the SF period (experienced birds) and in C chickens (naïve birds). In both experiments, total feed intake was similar among treatments and the percentage of each feed consumed was not significantly different from controls (50%). In experiment 1, S_E and S_E′ chickens over-consumed E+ and under-consumed E− diets only during the first 15 min of the fourth cycle. The choice test indicated that experienced chickens preferred E+, while naïve chickens preferred E−. Similarly, in experiment 2, chickens over-consumed E+ and E+P− during the first 15 min of the fourth cycle, but the intake of diets varying in protein content was not different from controls. During the choice test, as in experiment 1, experienced chickens preferred E+, while naïve chickens preferred E−. There was a slight preference for the protein-poor diet in naïve birds and there was no preference in the diet varying in both protein and energy contents. Experience modified choice between feeds varying in energy content but not in protein. When feeds were known, preference for energy affected the feed intake immediately after switching from one diet to the other, although lower with the diet also varying in protein, it did not influence the total intake of each diet. Interactions between the nutritional properties and sensorial cues of feed could explain these results.     

Effects of in ovo feeding of creatine pyruvate on the hatchability,growth performance and energy status in embryos and broiler chickens

The effects of in ovo feeding (IOF) of creatine pyruvate (CrPyr) on the hatchability, growth performance and energy status of embryos and broilers (Arbor Acres) were investigated. Five treatments were arranged as non-injected treatment (Control), 0.6 ml physiological saline (0.75%) injected treatment (Saline), and IOF treatments injected with 0.6 ml physiological saline (0.75%) containing 3, 6 or 12 mg CrPyr (CrPyr₃, CrPyr₆ or CrPyr₁₂) into the amnion per fertile egg on day 17.5 of incubation. After hatching, 80 male chicks from each treatment with similar weight close to the average BW of their pooled group were selected and randomly assigned into eight replicates of 10 chicks each. The results showed that the hatchability was not affected among groups, whereas the hatching weight of broilers in CrPyr₁₂ was significantly higher than the control and saline groups (P<0.05). At 21 day post-hatch, the BWs of broilers in CrPyr₆ and CrPyr₁₂ were increased relative to the control and saline groups (P<0.05). Chickens in CrPyr₆ and CrPyr₁₂ exhibited higher BW gain and feed intake than the control and saline groups during 8 to 21 days post-hatch and the entire experiment period (P<0.05). Compared with the control and saline groups, the total and relative weight of pectoral muscle of embryos or chickens were greater in CrPyr₆ and CrPyr₁₂ at 19^th day of incubation (19 E), hatch, 3 and 21 days post-hatch (P<0.05). The concentrations of glucose and glycogen in liver were increased in CrPyr₆ and CrPyr₁₂ at 19 E and hatch (P<0.05). Neither glycogen nor glucose concentration in pectoral muscle was altered among treatments (P>0.05). Irrespective of dosage, the concentrations of creatine and phosphocreatine, and activities of creatine kinase in embryos were enhanced in CrPyr treatments at 19 E when compared with the control and saline groups (P<0.05). The activities of glucose-6-phosphatase in liver in CrPyr₆ and CrPyr₁₂ treatments were higher than the control and saline groups at 19 E (P<0.05). In conclusion, these results indicated that IOF of CrPyr, especially at the level of 12 mg/egg, could improve energy status of embryos and hatchlings, which was useful for enhancing hatching weight, BW and pectoral muscle weight until the end of the experiments at 21 days post-hatch in broilers.     

Effects of dietary soybean protein levels on energy budget of the southern catfish, Silurus meridionalis

Energy budgets were calculated for the southern catfish, Silurus meridionalis, fed diets replacing 0%, 13%, 26%, 39%, 52% and 65% fish meal protein with soybean meal (SBM) protein with or without methionine supplementation to apparent satiation at 27.5 °C. With increasing dietary soybean protein levels (SPL), the feed energy lost in feces, excretion and metabolism increased, while that available for growth decreased (P < 0.05). When 0.12% or 0.26% methionine at 39% SPL was added to reach that in body carcass or the control group (0% SPL), no significant differences were found in each component of energy budgets. When 0.21% or 0.33% methionine at 52% SPL was added to reach the content of methionine in body carcass or the control group, energy spent on growth increased, but that on excretion and metabolism decreased (P < 0.05). These results suggested that the differences in growth rate among the southern catfish fed the diets with different SPL were due to decreasing absorption rate, increasing excretion and metabolism with increasing dietary SPL. The most important factor limiting the use of soybean protein was the imbalance of essential amino acids, which resulted in more energy spent on metabolism and excretion, less energy on growth. Supplementation of methionine produced a relatively better amino acid profile and subsequently improved the utilization of soybean protein at high SPL, which resulted in less energy used for metabolism or lost in excretion and more energy available for growth.     

Effects of feed form and energy levels on growth performance,carcass yield and nutrient digestibility in broilers

Feed form is well recognized to improve broiler performance, specially by increasing feed intake (FI). However, when different diet energy levels are used, the results differ in the literature. Therefore, this experiment was conducted to evaluate the influence of feed form and dietary metabolizable energy (ME) levels on broiler performance, carcass yield and on the digestibility of DM, CP, starch and gross energy. In total, 1152 male Cobb 500 broilers were evaluated between 35 and 47 days. The birds were distributed according to a completely randomized design in a 2 × 4 factorial arrangement, consisting of two feed forms (mash or pellet) and four ME levels (12.73, 13.06, 13.40 or 13.73 MJ/kg), totaling eight treatments with eight replicates of 18 birds. Broilers fed the lowest ME level presented the lowest weight gain (WG) and worst feed per unit gain (P < 0.01). Metabolizable energy intake increased (P < 0.01) with progressive increments of ME, which, however, did not affect caloric conversion (CC, P > 0.05). Pelleted diets promoted higher FI, WG, ME intake (P < 0.01) and better feed per unit gain and CC (P < 0.05) compared with mash. In mash diets, increasing dietary ME levels promoted a linear increase in WG (P < 0.01) and reduced feed per unit gain (P ≤ 0.05), but did not affect FI (P > 0.05). In pelleted diets, on the other hand, increasing ME levels linearly reduced FI (P < 0.05) and feed per unit gain (P < 0.01). Broilers fed pelleted diets presented higher abdominal fat deposition than those fed mash (P < 0.05). Increasing ME levels reduced the coefficients of ileal apparent digestibility of DM (P < 0.01) and total starch (P < 0.05) but did not affect the digestibility of other evaluated nutrients. The digestibility of all nutrients was lower when pelleted diets were fed compared with mash. Increasing inert material inclusion in the diets at the expense of soybean oil to reduce dietary ME levels promoted higher pellet durability index values (P < 0.05) and the percentage of fines (P < 0.01). Overall, the results suggest that pelleted diets promote better broiler performance because they increase FI, since the digestibility of dietary fractions is reduced. Chickens consuming low-energy pelleted diets may increase FI to compensate for energy deficit. In contrast, broilers fed mash diets may have reached their maximum intake capacity and did not regulate FI by changing feed energy density. When feeding pelleted diets, dietary energy reduction should be considered to reduce feed costs and to improve the carcass quality of broilers.     

Effects of chronic heat exposure and protein intake on growth performance, nitrogen retention and muscle development in broiler chickens

The respective effects of ambient temperature, dietary crude protein and feed intake were investigated in finishing chickens and the consequence of protein supplementation under high temperature conditions was analysed in particular. Heat-related reduction in growth was associated with decreased nitrogen retention (-30 or -35% according to the diet), which could not be explained by the observed lower feed intake alone. Tissue samples performed in 5- to 6-week-old chicks showed varying effects of heat according to the muscles studied: at 32 degrees C, the proportion of Pectoralis major muscle (in percentage of body weight) appeared slightly reduced (reduction lower than 10%), whereas the proportion of two leg muscles were increased (+10 to +15% for the Sartorius muscle; +5% for the gastrocnemius muscle). At 32 degrees C, providing a high protein diet significantly (P < 0.05) increased weight gain and feed efficiency, and slightly improved whole body protein deposition.     

Effects of dietary inclusion of triticale,rye and wheat and xylanase supplementation on growth performance of broiler chickens and fermentation in the gastrointestinal tract

An experiment was performed over a period of 5 weeks with 576 one-day-old cockerels (Cobb 500), which were randomly divided into 6 experimental groups (12 replicate cages with 8 birds/cage). The objective of the experiment was to estimate whether different grain types (wheat, rye or triticale) and exogenous xylanase inclusion influence the performance and the gastrointestinal ecosystems of broiler chickens as regards intestinal viscosity, pH as well as the concentration of short-chain fatty acids (SCFA) and lactic acid (LA). The rye-based diets resulted in the poorest production results followed by wheat and triticale-based diets. Ileal viscosity decreased in the range: rye (140 cps), triticale (6.1 cps) and wheat (2.5 cps). Xylanase supplementation reduced ileal viscosity significantly only in birds fed with rye. The cereal type influenced the fermentation process in the broiler gastrointestinal tract more than the xylanase supplementation. The total concentration of organic acids was highest in the caeca, followed by the crop, ileum and gizzard. Lactic acid concentrations were highest in the content of the crop followed by ileum, gizzard and caeca. Propionate was only detected in caecal contents, whereas butyrate was also found in small amounts in the contents of the crop of birds from all treatments. The concentrations of acetate, butyrate and total organic acid concentration in caecal contents of chickens receiving the rye-based diets were lower than in birds fed the other cereals (P<0.001). Enzyme supplementation reduced the relative weight of the caeca in rye-fed birds (P=0.001).     

Effects of dietary arginine levels on growth performance and body composition of juvenile grouper Epinephelus coioides

An 8‐week feeding trial was conducted to determine the effects of dietary arginine levels on growth performance and body composition of juvenile grouper Epinephelus coioides (initial weight: 16.10 ± 0.26 g per fish) in 500‐L indoor flow‐through circular fiberglass tanks. Diets contained six levels of l ‐arginine ranging from 1.78% to 3.31% of dry diet in 0.30% increments. The diets, in which 25% crude protein came from fishmeal and soybean protein concentrate, and 23% from crystalline amino acids, were formulated to simulate the amino acid profile of 48% whole chicken egg protein except for arginine. Each diet was assigned to three tanks (20 fish per tank) in a completely randomized design. Grouper were fed to apparent satiation (about 5% body weight per day at the initial 1–4 weeks and 3% body weight per day in the following 5–8 weeks) twice daily on weekdays and once daily on weekends. Weight gain (WG) and specific growth rate (SGR) showed an incremental trend with increasing dietary arginine levels from 1.78% to 2.72% and remained thereafter relatively constant. Productive protein value (PPV) was poorest in fish fed the lowest arginine diet (P < 0.05) and showed no significant differences among other treatments (P > 0.05). Dietary arginine contents significantly influenced body composition. With the increase in dietary arginine, contents of total essential amino acids (EAAs), total non‐EAAs and total amino acids of whole body significantly increased (P < 0.05). The retention of dietary EAA in whole body of juvenile grouper was significantly influenced by dietary arginine. Arginine retention increased with increasing dietary arginine levels from 1.78% to 2.72%, then declined above the level of 2.7% (P < 0.05). Based on broken‐line regression analysis of WG against dietary arginine levels, the dietary arginine requirement of juvenile grouper E. coioides was determined as 2.7% of the diet (corresponding to 5.5% of dietary protein).     

Effects of dietary lipids and Clostridium butyricum on the performance and the digestive tract of broiler chickens

The effects of two sources of dietary lipids and supplementation of Clostridium butyricum on performance and intestinal metabolism of broilers were investigated. In a 2 x 2 factorial arrangement, 168 one-day-old broiler chicks were divided into four treatment groups, and fed four diets with two lipid sources (soya bean oil or fish oil, at 25 g/kg and 30 g/kg in starter and grower diets respectively), and without or with supplementation of C. butyricum (1 x 10(9) colony forming units per kg diet). C. butyricum had no effect on broiler performance. At 20 and 40 d of age, the pH of caecal digesta and the relative length of caecum were decreased after supplementation of C. butyricum (p < 0.05). After this treatment, the activity of alkaline phosphatase was increased in jejunal mucosa at 40 d of age (p < 0.01). Furthermore, there were increases in populations of lactic acid bacteria and the concentrations of acetic acid, n-butyric acid, n-valeric acid and total short chain fatty acids in caecal digesta of birds fed C. butyricum (p < 0.05). A significant interaction between lipid source and C. butyricum was found in the pH of caecal digesta at 20 d of age (p < 0.01). The results of the present study indicated that dietary supplementation of C. butyricum maybe a benefit for gut health of broiler chickens.     

Effects of sex and dietary phosphorus level on the apparent metabolizable energy and nutrient digestibility in broiler chickens

The influence of sex of broilers and dietary phosphorus (P) level on energy utilization and apparent ileal digestibility of N, P and phytate-P were investigated. The AME(N) was determined using 3- and 6-week old broilers, while the apparent ileal digestibility were determined only with 6-week old birds. Sex of broilers had no effect on the AME(N) values determined during week 3. During week 6, the AME(N) values for male broilers were higher (P < 0.01) than those for the females. An interaction (P < 0.05) between sex and dietary P level was also observed. AME(N) values determined with male broilers were lower in the adequate-P diet compared to those in the low-P diet, whereas no effect of P level was observed in females. Female broilers tended (P < 0.10) to have a higher ileal N digestibility than the males, but a significant (P < 0.01) sex x P level interaction was observed. Males receiving the adequate-P diet had a lower N digestibility than those receiving the low-P diet, whereas the opposite was true in the females. Ileal phytate P degradation in males was higher than in females (0.282 vs. 0.234), but the differences were not significant. Increasing dietary P level increased ileal P digestibility in both the males and females, but the improvements were greater in the females, as indicated by a significant sex x P level interaction.     

Effects of sex and dietary phosphorus level on the apparent metabolizable energy and nutrient digestibility in broiler chickens

The influence of sex of broilers and dietary phosphorus (P) level on energy utilization and apparent ileal digestibility of N, P and phytate-P were investigated. The AME_N was determined using 3- and 6-week old broilers, while the apparent ileal digestibility were determined only with 6-week old birds. Sex of broilers had no effect on the AME_N values determined during week 3. During week 6, the AME_N values for male broilers were higher (P?0.01) than those for the females. An interaction (P?0.05) between sex and dietary P level was also observed. AME_N values determined with male broilers were lower in the adequate-P diet compared to those in the low-P diet, whereas no effect of P level was observed in females. Female broilers tended (P?0.10) to have a higher ileal N digestibility than the males, but a significant (P?0.01) sex ×?P level interaction was observed. Males receiving the adequate-P diet had a lower N digestibility than those receiving the low-P diet, whereas the opposite was true in the females. Ileal phytate P degradation in males was higher than in females (0.282 vs. 0.234), but the differences were not significant. Increasing dietary P level increased ileal P digestibility in both the males and females, but the improvements were greater in the females, as indicated by a significant sex × P level interaction.     

Comparing protein abundance and mRNA expression levels on a genomic scale

Attempts to correlate protein abundance with mRNA expression levels have had variable success. We review the results of these comparisons, focusing on yeast. In the process, we survey experimental techniques for determining protein abundance, principally two-dimensional gel electrophoresis and mass-spectrometry. We also merge many of the available yeast protein-abundance datasets, using the resulting larger 'meta-dataset' to find correlations between protein and mRNA expression, both globally and within smaller categories.     

Effects of dietary iron levels on growth performance, hematological status, liver mineral concentration, fecal microflora, and diarrhea incidence in weanling pigs

An experiment was conducted in weanling pigs (Landrace x Yorkshire x Duroc) to evaluate the effects of dietary iron levels on growth performance, hematological status, liver mineral concentration, fecal microflora, and diarrhea incidence. One hundred and forty-four piglets (initial BW 5.96 +/- 0.93 kg) were randomly allotted to one of the four dietary treatments on the basis of their body weights. The basal diets for each phase (phase 1: days 0 to 14; phase 2: days 15 to 28) were formulated to contain minimal Fe and then supplemented with gradient levels of Fe (0, 50, 100, and 250 mg/kg) from ferrous sulfate. Feces were collected on days 14 and 28 and used for the analysis of microbial count and trace minerals. Eight piglets from each treatment (two piglets per pen) were bled at 0, 7, 14, 21, and 28 days to determine their hematological and plasma Fe status. In addition, two piglets from each pen (eight piglets per treatment) were killed at days 14 and 28 to determine liver mineral concentrations. Pigs fed supplemental 250 ppm Fe showed lowest overall average daily gain (linear, p = 0.036). Diarrhea incidence was linearly increased (p < 0.001) with supplemental Fe level. On days 14, coliform population in normal feces was increased (p = 0.036) linearly with supplemental Fe level, and there were higher (p = 0.043) coliform population and lower (p < 0.001) Bifidobacterium spp. in the diarrhea feces. Supplemental Fe linearly (p < 0.05) improved the total red blood cells, hemoglobin, plasma, and liver (p = 0.109) Fe status of pigs and also increased (linear and quadratic, p < 0.001) the fecal excretion of Fe on days 14 and 28. It is concluded that increasing the dietary iron levels in piglets improved their hematological status and liver Fe content; however, higher dietary Fe levels might also be associated with the increased diarrhea incidence.