Comparative evaluation of net digestive and absorptive efficiency in dogs and cats fed a variety of contrasting diet types

Comparative net digestive and absorptive efficiency was assessed with adult Beagles and domestic cats by apparent digestibility assays. Eight foods were used comprising two canned dog foods; canned cat foods; two samples of semipurified diet; and single samples of experimental dry cat food and fresh mince. Apparent digestibility percentages of crude protein, fat, nitrogen-free extract (NFE) and gross energy were all significantly higher in dogs than cats. Mean values obtained for dogs were (per cent): crude protein 87; fat 92; NFE 70 and energy 89. Respective values for cats were 82, 76, 67 and 79. On average, dogs obtained 11 and 9 per cent more digestible energy and protein per unit food eaten than cats. Most digestibility characteristics of foods measured in cats were significantly correlated with those for dogs and regression equations are presented predicting digestibility in cats from dog data.     

Determining metabolizable energy content in commercial pet foods

This study was conducted to assess the suitability of several equations for the estimation of metabolizable energy (ME) of pet foods. Sixteen canned and 31 dry cat foods and 24 dry dog foods representing the range of energy densities found in commercial adult, growth or all life stage products were evaluated in four separate experiments. In vivo ME was compared with estimates of ME generated by several previously published equations. The results indicated that the equation recommended by Association of American Feed Control Officials provided reasonable estimates of in vivo ME for both canned cat foods and dry dog foods, but proved unsuitable for dry cat foods. Better estimates were generated in each case using other published equations. Of the equations tested, the most accurate equations for estimating ME (kJ/g) without feeding trials were:
for canned cat foods: [(16.32 × protein) + (32.22 × fat) + (12.55 × NFE)];
for dry cat foods: [((GE × 1.209) – 1.911) × 4.184] or [((0.075 × g fat) + 2.766) × 4.184]
for dry dog foods: [GE=(24 × g protein) + (38 × g fat) + (17 × g NFE), then percentage energy digestibility=91.2 – (1.43 × percentage crude fibre in dry matter), then ME=(GE × percentage energy digestibility) – (4.34 × g protein)].
With the exception of high-fibre weight-management diets, the simple equation [((GE × 1.209)–1.911) × 4.184] also reliably predicted ME in dry dog foods.     

Prediction of nutritive values in grass silages: I. Nutrient digestibility and energy concentrations using nutrient compositions and fermentation characteristics

Grass silages (n = 136) were selected from commercial farms across Northern Ireland according to their pH, ammonia nitrogen, DM, and predicted ME concentration. Each silage was offered to four sheep as a sole feed at maintenance feeding level to determine nutrient digestibility and urinary energy output. Dry matter concentration was determined as alcohol-corrected toluene DM and was subsequently used as the basis for all nutrient concentrations. The objectives were to use these data to examine relationships between nutritive value and nutrient concentration or fermentation characteristics in silages and then develop prediction equations for silage nutritive values using stepwise multiple regression techniques. The silages had a large range in quality (DM = 15.5 to 41.3%, ME = 7.7 to 12.9 MJ/kg of DM, pH = 3.5 to 5.5) and a relatively even distribution over the range. There was a positive relationship (P < 0.001) between silage GE and DE or ME concentration. Digestible OM in total DM (DOMD); ME/GE; and digestibility of DM, OM, and GE were positively related (P < 0.05) to CP, soluble CP, ether extract, lactic acid concentration, and lactic acid/ total VFA, whereas they were negatively related (P < 0.05) to ADF, NDF, lignin, individual VFA concentration, pH, and ammonia N/total N. Concentrations of DE and ME and digestibility of CP and NDF had similar relationships with those variables, although some relationships were not significant. Three sets of multiple prediction equations for DE and ME concentration; ME/ GE; DOMD; and digestibility of DM, OM, GE, CP, and NDF were therefore developed using three sets of predictors. The first set included GE, CP, soluble N/total N, DM, ash, NDF, lignin, lactic acid/total VFA, and ammonia N/total N; the second set excluded soluble N/ total N and lignin because they are not typically measured; the third set further excluded the fermentation data. The R2 values generally decreased with exclusion of predictors. The second and third sets of equations, except for NDF digestibility, were validated using the mean-square-prediction-error model and an independent grass silage data set published since 1977 (n = 17 [DM digestibility] to 28 [DOMD and OM digestibility]). The validation indicated that the equations developed in the present experiment could accurately predict DE and ME concentrations and DE/GE and ME/GE in grass silages.     

The development of a metabolizable energy system for horses

The development of a metabolizable energy (ME) system for horses is described. Predictive equations for gross energy and digestible energy (DE) are revisited. The relationship between feed protein content and renal energy losses and the relationship between feed fibre content and methane energy losses were analysed in a literature review to develop predictive equations for ME. In horses, renal energy losses are much higher than losses by methane energy. Renal energy losses were correlated more strictly to protein intake than to digestible protein intake. The reason probably is that per gram of digestible crude protein energy losses are higher for roughage than for concentrates presumably because phenolic acids of forage cell walls contribute to higher urinary energy losses. However, digestibility of protein is lower in forages than in concentrates. The net result is a rather constant urinary energy loss of 0.008 MJ/g of crude protein in the feed. Methane losses in horses are smaller than in ruminants, presumably because of reductive acidogenesis in hind gut fermentation. Methane energy losses in equines are closely related to crude fibre intake. The mean methane energy losses amount to 0.002 MJ ME/g of crude fibre which can be used to correct for methane losses. Both corrections can be made for any predictive equation for DE. Metabolizable energy is then calculated as follows: ME MJ/kg = DE MJ/kg – 0.008 MJ/g crude protein – 0.002 MJ/g crude fibre. The equation of Zeyner and Kienzle (2002) to predict DE was adapted as mentioned above to predict ME: ME (MJ/kg dry matter) = ?3.54 + 0.0129 crude protein+0.0420 crude fat?0.0019 crude fibre+0.0185 N‐free extract (crude nutrients in g/kg dry matter).     

Energy evaluation of extruded compound foods for dogs by near-infrared spectroscopy

Near-infrared reflectance spectroscopy (NIRS) was used to predict the chemical composition, apparent digestibility and digestible nutrients and energy content of commercial extruded compound foods for dogs. Fifty-six foods of known chemical composition and in vivo apparent digestibility were analysed overall and 51 foods were used to predict gross energy digestibility and digestible energy content. Modified partial least square calibration models were developed for organic matter (OM), crude protein (CP), ether extract (EE), crude fibre (CF), nitrogen free extracts (NFE) and gross energy (GE) content, the apparent digestibility (OMD, CPD, EED, NFED and GED) and the digestible nutrient and energy content (DOM, DCP, DEE, DNFE and DE) of foods. The calibration equations obtained were evaluated by the standard error and the determination coefficient of cross-validation. The cross-validation coefficients of determination (R) were 0.61, 0.99, 0.91, 0.96, 0.94 and 0.92 for OM, CP, EE, CF, NFE and GE, the corresponding standard error of cross-validation (SECV) being 5.80, 3.51, 13.35, 3.64 and 16.95 g/kg dry matter (DM) and 0.29 MJ/kg DM respectively. The prediction of apparent digestibility was slightly less accurate, but NIRS prediction of digestible nutrient (g/kg DM) and DE (MJ/kg DM) gave satisfactory results, with high R (0.93, 0.97, 0.93, 0.83 and 0.93 for DOM, DCP, DEE, DNFE and DE respectively) and relatively low SECV (11.55, 6.85, 12.14 and 22.98 g/kg DM and 0.47 MJ/kg DM). It is concluded that the precision of NIRS in predicting the energy value of compound extruded foods for dogs is similar or better than by proximate analysis, as well as being faster and more accurate.     

直接法和回归法测定玉米青贮对肉牛有效能值的研究

旨在应用直接法和回归法测定肉牛玉米青贮的消化能、代谢能和净能值,并探讨精料回归法用于估测肉牛单一粗饲料原料能值的可行性。试验选取12头体况良好、体重相近[(259±14.08)kg]的生长期公牛,随机分为3组,每组4头牛。分两期试验进行,试验一按试验牛自由采食量的95%、80%和60%3个水平饲喂全玉米青贮日粮;试验二在固定玉米青贮投喂量的基础上,各组分别按青贮饲喂量的15%、25%和50%(干物质基础)添加精料补充料。试验每期14d,其中前10d为预饲期,后4d为正试期。正试期消化代谢和呼吸代谢试验同期进行,测定玉米青贮对肉牛能量代谢规律。结果表明:1)肉牛对全玉米青贮日粮的各种营养物质消化率和能量消化率及代谢率随饲喂水平的提高总体逐渐降低;肉牛能量采食量(总能、消化能、代谢能和净能)随饲喂水平的提高逐渐升高,组间差异显著(P0.05)。2)玉米青贮对肉牛的消化能、代谢能和净能值随着饲喂水平的提高呈下降趋势,各有效能值变化范围分别为10.58~11.48 MJ/kg,8.33~9.44 MJ/kg和5.20~6.21 MJ/kg。3)添加精料补充料显著提高了肉牛对日粮的干物质采食量和粗蛋白消化率(P0.05),而洗涤纤维消化率精料添加比例组间差异不明显(P0.05);随着精料添加比例的增加,肉牛对日粮的能量采食量(总能、消化能、代谢能和净能)和能量消化率及代谢率逐渐上升,消化能代谢率各组之间无显著差异(P0.05)。4)根据试验日粮有效能值与精料添加量之间的关系建立线性回归方程后,外推估测得玉米青贮的消化能、代谢能和净能值分别为10.53 MJ/kg、8.29 MJ/kg和5.35MJ/kg,与95%饲喂水平组直接测定结果(10.58 MJ/kg、8.33 MJ/kg和5.20 MJ/kg)差异不显著(P0.05)。综上所述,回归法测定玉米青贮对肉牛的有效能值与直接法测定结果差异不明显,精料回归法可以用于估测肉牛单一粗饲料的有效能值。     

肉用绵羊饲粮营养物质消化率和代谢能预测模型的研究

本试验旨在建立肉用绵羊饲粮营养物质消化率和代谢能(ME)的预测模型。选用66只体重为(45.0±2.0)kg的体况良好的杜泊×小尾寒羊F1代杂交肉用羯羊,随机分为11个处理,每个处理6个重复,每个重复1只羊。采用随机区组设计,分别测定11种不同粗饲料组成的饲粮的营养物质含量,通过物质代谢试验和气体代谢试验测定这11种饲粮的营养物质消化率、消化能(DE)及ME,在分析饲粮营养物质含量、可消化营养物质、DE和ME的基础上,筛选出最佳估测因子并建立估测方程。结果表明:饲粮干物质(DM)、有机物(OM)、粗蛋白质(CP)、总能(GE)消化率与饲粮中CP、GE和OM含量呈显著或极显著正相关(P0.05或P0.01),与中性洗涤纤维(NDF)含量呈显著负相关(P0.05);饲粮NDF消化率与饲粮中DM、OM、CP、GE含量达到显著或极显著负相关(P0.05或P0.01),与NDF含量达到极显著正相关(P0.01)。利用饲粮中营养物质含量对ME进行估测的最佳方程为ME=-49.593+0.594OM-0.107NDF(R2=0.949,P0.01)。由此得出,饲粮营养物质消化率、ME与营养物质含量均有较强的相关性,可通过营养物质含量对饲粮的营养物质消化率、ME进行合理估测。     

陕北白绒山羊羯羊能量和蛋白质需要量

本试验旨在研究陕北白绒山羊羯羊能量和蛋白质的需要量,为制定其饲养标准提供数据。选取36只体重相近、健康状况良好的陕北白绒山羊周岁羯羊,按3×3(能量×蛋白质)完全随机设计分为9组,每组4个重复,每个重复1只。各组饲粮消化能和粗蛋白质水平分别参照NRC(1981)推荐量的100%、110%、120%和90%、110%、130%设定。预试期7 d,正试期46 d。结果表明:1)饲粮能量水平对周岁羯羊的干物质采食量和平均日增重都有极显著影响(P0.01),蛋白质水平对干物质采食量影响显著(P0.05);饲粮能量和蛋白质水平对干物质采食量有显著的互作效应(P0.05)。2)低能量水平组的可消化氮显著低于中能量水平组与高能量水平组(P0.05);低蛋白质水平组的进食氮、可消化氮、沉积氮、氮表观消化率均极显著低于中蛋白质水平组和高蛋白质水平组(P0.01)。3)总能消化率和总能代谢率均随着能量水平的提高而极显著地升高(P0.01);高蛋白质水平组的总能代谢率和消化能代谢率显著低于低蛋白质水平组(P0.05);能量和蛋白质水平对总能消化率、总能代谢率和消化能代谢率均产生显著或极显著的互作效应(P0.05或P0.01)。本试验得到了陕北白绒山羊周岁羯羊能量和蛋白质需要量的回归方程,饲粮的消化能和代谢能分别以8.80~10.61 MJ/kg和7.34~8.76 M J/kg较为适宜,粗蛋白质和可消化粗蛋白质分别以10.00%和7.34%为宜。     

Determination and prediction of digestible and metabolizable energy from chemical analysis of corn coproducts fed to finishing pigs

Twenty corn coproducts from various wet- and dry-grind ethanol plants were fed to finishing pigs to determine DE and ME and to generate equations predicting DE and ME based on chemical analysis. A basal diet comprised corn (97.05%), limestone, dicalcium phosphate, salt, vitamins, and trace minerals. Twenty test diets were formulated by mixing the basal diet with 30% of a coproduct, except for dried corn solubles and corn oil, which were included at 20 and 10%, respectively. There were 8 groups of 24 finishing gilts (n = 192; BW = 112.7 ± 7.9 kg). Within each group, gilts were randomly assigned to 1 of 5 test diets or the basal diet for a total of 4 replications per diet per group. Two groups of gilts were used for each set of coproducts, resulting in 8 replications per coproduct and 32 replications of the basal diet. The experiment was conducted as a completely randomized design. Gilts were placed in metabolism crates and offered 3 kg daily of their assigned test diet for 13 d, with total collection of feces and urine during the last 4 d. Ingredients were analyzed for DM, GE, CP, ether extract, crude fiber, NDF, ADF, total dietary fiber (TDF), ash, AA, and minerals, and in vitro OM digestibility was calculated for each ingredient. The GE was determined in the diets, feces, and urine to calculate DE and ME for each ingredient. The DE and ME of the basal diet were used as covariates among groups of pigs. The DE of the coproducts ranged from 2,517 kcal/kg of DM (corn gluten feed) to 8,988 kcal/kg of DM (corn oil), and ME ranged from 2,334 kcal/kg of DM (corn gluten feed) to 8,755 kcal/kg of DM (corn oil). By excluding corn oil and corn starch from the stepwise regression analysis, a series of DE and ME prediction equations were generated. The best fit equations were as follows: DE, kcal/kg of DM = -7,471 + (1.94 × GE) - (50.91 × ether extract) + (15.20 × total starch) + (18.04 × OM digestibility), with R(2) = 0.90, SE = 227, and P < 0.01; ME, kcal/kg of DM = (0.90 × GE) - (29.95 × TDF), with R(2) = 0.72, SE = 323, and P < 0.01. Additional equations for DE and ME included NDF in the instance that TDF data were not available. These results indicate that DE and ME varied substantially among corn coproducts and that various nutritional components can be used to accurately predict DE and ME in corn coproducts for finishing pigs.     

Comparative total tract digestibility of dietary energy and nutrients in growing pigs and adult sows

Seventy-seven diets were fed to 61-kg growing pigs at a feeding level close to their ad libitum intake and to nonlactating, nonpregnant sows slightly above their maintenance energy level (2.4 kg/d). The main objectives of this study were to compare the total tract digestibility of dietary energy or nutrients of the 77 diets in growing pigs and adult sows and to analyze the effect of diet chemical composition on total tract digestibility in both groups of pigs. Diets were formulated to represent a range of chemical compositions as large as those found in most practical situations. The DE and ME values and total tract digestible nutrient contents of diets were measured for each group of animals; each diet was measured in four to five animals per group, and collection of urine and feces lasted 10 d. The results were used to establish equations for predicting DE and ME values, total tract digestible nutrient contents, and total tract digestibility coefficients of energy from chemical characteristics for each group of animals. The results show that the total tract digestibility of energy or nutrients was higher (P < 0.01) in adult sows than in growing pigs; the total tract digestibility coefficients of energy, crude protein, ether extract, and NDF averaged 85.2, 85.1, 37.1, and 64.4%, respectively, for sows and 82.1, 80.3, 31.6, and 56.3%, respectively, for growing pigs. The ME/DE ratio was lower (P < 0.01) in sows (94.8%) than in growing pigs (96.5%), as a result of higher urinary energy losses in sows. The difference in DE values (on average, 0.6 MJ/kg of DM) between adult sows and growing pigs was not constant (P < 0.01) but increased with dietary fiber content (3.3, 8.6, and 10.1 kJ for each gram of NDF, ADF, and crude fiber increase in the diet, respectively), which suggests that the origin of the difference between the two physiological stages is mainly due to a higher rate of degradation of dietary fiber in the hindgut of sows. The DE and ME values could be accurately predicted from total tract digestible nutrients or from chemical characteristics for each physiological stage. Equations for predicting urinary energy loss from urinary N are also proposed. From a practical point of view, it is suggested to use two energy values for pig feeds: one applicable to growing-finishing pigs and one to adult sows. Equations for predicting DE in adult sows from energy values obtained in growing pigs are proposed.     

Feeding different dietary protein to energy ratios to Holstein heifers: effects on growth performance,blood metabolites and rumen fermentation parameters

Eighteen Chinese Holstein heifers average age 230 ± 14 days were allocated to 1 of 3 dietary crude protein (CP) to metabolizable energy (ME) ratios to examine the effects on growth performance, blood metabolites and rumen fermentation parameters with 90‐days experiment. Three different dietary CP:ME ratios were targeted based on the formulation of dietary CP contents of 10.85%, 12.78% and 14.63% on dry matter (DM) basis with similar ME contents (10.42 MJ/kg DM), which were categorized as low, medium and high dietary CP:ME ratios. The actual CP:ME ratios obtained in this study significantly increased from low to high CP:ME ratio groups with a value of 10.59, 11.83 and 13.38 g/MJ respectively. Elevated CP:ME ratios significantly increased CP intake (kg/day) and feed efficiency (FE) which was defined as dry matter intake as a proportion of average daily gain (ADG), whereas little difference was observed in body weight (kg), ADG (kg/day), DM intake (kg/day) and ME intake (MJ/day) among the three different CP:ME ratio groups. Increasing dietary CP to ME ratios significantly increased CP digestibility, whereas digestibility of DM and gross energy remained constant in the current experiment. Blood urea nitrogen and insulin‐like growth factor‐1 linearly increased with increasing dietary CP:ME ratios. There was significantly dietary treatment effect on rumen fermentation parameters including acetate, propionate, butyrate and total volatile fatty acids. Therefore, this study indicated that increasing dietary CP levels with similar energy content contributed to increased protein intake and its digestibility, as well as FE. Holstein heifers between 200 and 341 kg subjected to 13.38 dietary CP:ME ratio showed improved feed efficiency, nutrient digestibility, some blood metabolites and rumen fermentation characteristics for 0.90 kg/day rate of gain.     

Chemical composition,energy and amino acid digestibility in double-low rapeseed meal fed to growing pigs

Background:The nutritional value of rapeseed meal may be variable due to the variation of its chemical composition.And a precise understanding of the nutritional value of an ingredient is beneficial for the accurate diet formulation and reduction of feed costs.This study was conducted to determine the chemical composition,digestible energy(DE) and metabolizable energy(ME) content,and apparent ileal digestibility(AID) and standardized ileal digestibility(SID) of amino acids(AA) for growing pigs.Thirteen solvent-extracted double-low rapeseed meal(DLRSM) samples were obtained from the main double-low rapeseed producing areas in China.Methods:The DE and ME contents of the 13 DLRSM samples were measured in growing pigs(six pigs per DLRSM sample,average initial body weight(BW) = 48.3 kg).The AID and SID of AA of 10 DLRSM samples were determined in 12 crossbred barrows(average initial BW = 35.3 kg) by using two 6x6 Latin square designs.Each Latin square comprised one N-free diet and 5 DLRSM test diets.Results:The chemical composition of DLRSM varied among samples,and the coefficient of variation was greater than 10%for ether extract(EE),neutral detergent fiber(NDF),acid detergent fiber(ADF),calcium(Ca),and total glucosinolates.The AA content of DLRSM varied among samples especially for lysine(Lys) and methionine(Met).On a dry matter(DM) basis,the apparent total tract digestibility(ATTD) of gross energy(GE),the DE and ME and the ME:DE ratio of DLRSM averaged 62.39%,2862 kcal/kg and 2723 kcal/kg,and 94.95%,respectively.The mean value of SID of Lys was 70.52% which varied from 66.54-76.54%.The SID of crude protein(CP),Met,and threonine(Thr) averaged 72.81%,82.41%,and 69.76%,respectively.Conclusions:There was great variability in chemical composition especially in the concentration of EE,NDF and ADF,but no significant differences in energy content of the DLRSM samples were observed.In addition,the AID and SID of all AA were relatively similar among DLRSM samples except for that of Lys.     

Evaluation of bovine rumen contents as a feed for lambs

This study evaluated effects of increasing levels of dried rumen contents (DRC) on voluntary intake, growth performance, digestibility, nutritive value, N utilization, microbial protein supply (MPS), and purine derivatives excretion (PDE) of lambs fed with Afzelia africana basal forage. Sixteen lambs (13.7?±?0.1 kg body weight (BW)) were randomly assigned to one of the four eight diets containing 0, 200, 400 and 600 g DRC/kg dry matter (DM) in a completely random design. Intakes of concentrate, DM, crude protein (CP), organic matter (OM), digestible CP (DCP), digestible OM (DOM), digestible energy (DE) and metabolizable energy (ME), CP and OM digestibility, DOM, DCP, DE, ME, N intake and retention, weight gain, cost/kg BW gain, MPS and PDE increased with increasing DRC level up to 400 g/kg DRC and declined at 600 g/kg DRC (P?<?0.05; 0.01). Feed conversion ratio and DM digestibility declined as DRC level increased from 0 to 400 g/kg and peaked at 600 g/kg DRC (P?<?0.05; 0.01). Forage intake and DE/DCP ratio decreased (P?<?0.05; 0.01) progressively with increasing DRC level. Results indicate that DRC can be incorporated up to 400 g/kg in a compounded ration for sheep.     

Nutrient digestibility and energy value of sheep rations differing in protein level, main protein source and non-forage fibre source

Two in vivo digestion trials were conducted to evaluate the effects of diet's crude protein (CP) level, N degradability, and non-forage fibre source (NFFS) on nutrient digestibility and energy value of sheep rations. In each trial, rams were fed four isocaloric and isofibrous rations, differing in main protein and/or NFFS source. At the first trial, mean CP/metabolizable energy (ME) ratio of the diets was 17 g/MJ ME and at the second trial, 13 g/MJ ME. At both trials, the first ration contained cotton seed cake (CSC) and wheat bran (WB), the second CSC and corn gluten feed (CGF), the third corn gluten meal (CGM) and WB and the fourth CGM and CGF. Data of both trials were analysed in common as 2 x 2 x 2 factorial experimental design. Low N degradability (CGM) had positive effect on CP, neutral detergent fibre (NDF) and acid detergent fibre (ADF) digestibility of the ration. Those results suggest that an increase in rumen undegradable protein (RUP) content does not negatively affect nutrient digestibility of sheep rations. Corn gluten feed significantly elevated crude fibre (CF) digestibility, in comparison with WB. Rations having high CP/ME ratio had higher digestibility of CP in comparison with those having low CP/ME ratio; the opposite was true for ether extract, CF, NDF and ADF digestibilities. CP level x N degradability interaction negatively affected energy value of the rations that had high CP level and high N degradability. Former suggest that when CP content is high then N degradability should be low otherwise ration's ME is negatively affected. CP digestibility and coefficient q of the rations containing WB and having high N degradability (N degradability x NFFS interaction) were the lowest suggesting that the combination of CSC and WB negatively affected CP digestibility and energy value of the ration. This could be explained by a reduced microbial CP synthesis, or lower RUP digestibility or both.     

Comparison of feed preference and digestion of three different commercial diets for cats and ferrets

Diet preference and digestibility experiments were conducted using a total of 10 cats and 10 ferrets. The composition of the three different kinds of dry cat feed was as follows (each data are given in dry matter, DM): (i) normal diet (N): 95.3% DM, 33.7% crude protein (CP), 20.4% ether extract (EE), 37.6% nitrogen-free extract (NFE); (ii) 'light diet' (L): 94.2% DM, 31.6% CP, 10.7% EE, 52.2% NFE; (iii) 'veterinary diet' (D): 94.57% DM, 38.7% CP, 9.6% EE, 47.2% NFE. During the period of the preference test, the average daily dry matter intake (calculated with the mean of the three diets: 94.7% DM) was 98.0, 15.0 and 16.7 g DM in cats and 25.0, 7.3 and 8.1 g DM in ferrets. The preference rates of the three different diets, expressed in percentage of their total consumption, were as follows: 60.4% N (54.4 g DM), 12.4% L (12.1 g DM) and 27.2% D (26.6 g DM) in cats, and 46.2% N (11.6 g DM), 29.9% L (7.5 g DM) and 23.9% D (6.0 g DM) in ferrets. This indicates that cats and ferrets have a clear preference for diets of higher fat content. In all three diets, the digestibility of CP was significantly (p < 0.05) lower (70.1 +/- 5.4 vs. 75.9 +/- 5.8) while that of EE was significantly (p < 0.05) higher (95.6 +/- 1.5 vs. 89.4 +/- 5.3) in ferrets than in cats. The average digestible/metabolizable energy (DE/ME) ratio of feeds turned to be 95.6% for cats and 90.6% for the ferrets. From the data one can conclude that the ferret cannot be used as a model animal for cats either for preference or digestibility studies.     

花生秧作为肉用绵羊单一粗饲料有效能值的测定与估测

本试验旨在用套算法和插值法测定与估测肉用绵羊花生秧有效能值,确定替代法中饲粮中适宜花生秧替代比例,为单一秸秆饲料有效能值的测定与估测提供方法学上的参考。选用体重为(45.00±1.96)kg的体况良好的杜泊×小尾寒羊F1肉用成年羯羊54只,采用随机区组设计,分为9组,饲粮分别为基础饲粮、全花生秧饲粮和分别以10%、20%、30%、40%、50%、60%、70%花生秧替代基础饲粮的试验饲粮,每组6个重复,每个重复1只羊。预试期10 d,正试期9 d,其中气体代谢试验3 d,消化代谢试验6 d。结果表明:1)全花生秧饲粮组花生秧干物质(DM)表观消化率与20%、30%、40%组间差异不显著(P0.05),显著高于其他各组(P0.05)。全花生秧饲粮组花生秧有机物(OM)表观消化率与20%组差异不显著(P0.05),但显著高于其他各组(P0.05)。全花生秧饲粮组花生秧总能(GE)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、粗脂肪(EE)表观消化率显著高于10%组(P0.05),粗蛋白质(CP)表观消化率显著低于10%组(P0.05),与其他各组间差异不显著(P0.05)。2)花生秧消化能(DE)、代谢能(ME)均具有相同的规律,即全花生秧饲粮组DE、ME(8.57、6.69 MJ/kg DM)与20%(8.22、6.58 M J/kg DM)、30%(8.02、6.50 M J/kg DM)、40%组(8.10、6.52 M J/kg DM)差异不显著(P0.05),但显著高于其他组(P0.05)。3)插值法求得花生秧M E"真值"为6.62 M J/kg DM,接近于套算法得到的花生秧ME。综合得出,套算法可以用于肉用绵羊估测花生秧(单一粗饲料)的DE和M E;用套算法测定花生秧秸秆类粗饲料有效能值,其在饲粮中的适宜替代比例为20%~40%。     

Determination of the digestible energy intake and apparent absorption of macroelements in pasture-fed lactating Thoroughbred mares

AIM: To measure the nutritive value of pasture in terms of digestible energy (DE) intake (DEI) and dry matter (DM) digestibility, and to determine the apparent absorption of macroelements in lactating Thoroughbred mares grazed on pasture. METHODS: DM intake (DMI) and DEI were determined from daily faecal DM output measured in grazing mares, divided by the DM indigestible fraction (1-digestible DM), measured in a digestibility trial using pasture-fed mares. Eight lactating mares and their foals, that had a mean age of 40 days, were grazed separately on 50x100 m areas of pasture and daily faecal DM outputs were recorded for 8 days. Five mares and their foals were then placed in individual bare 20x20 m corrals containing custom-made feeding stations for 14 days to determine the indigestible DM fraction. DM, gross energy content, crude protein (CP), soluble carbohydrate, acid detergent fibre (ADF), neutral detergent fibre (NDF), lipid, and macroelement composition of the pasture offered and faeces were determined and their digestibility and/or apparent absorption calculated. RESULTS: DM digestibility of the pasture was 0.6 and the DMI and DEI of a grazing 560 kg mare in early lactation nursing a foal growing at 1.34 kg/day was 13.6 (SE 0.8) kg/day and 146.9 (SE 8.4) MJ DE/day, respectively. Apparent absorptions of the macroelements measured were: Ca 0.75, P 0.43, Mg 0.63, Na 0.78, and K 0.72. CONCLUSIONS: Good quality ryegrass-white clover pasture that had a DE content of 10.8 MJ/kg DM, and a macroelement composition (g/kg) of Ca 3.33, P 3.0, Mg 1.67, Na 1.67, and K 24.2, will provide adequate DMI, DEI, and macroelement intake to lactating Thoroughbred mares.     

山东省羊常用粗饲料营养价值评定

试验旨在综合评价从山东省17个市采集的羊常用粗饲料原料的营养价值。试验测定了109个样本10种常用原料的常规营养成分及总能(GE),应用两级离体消化法测定干物质消化率(IVDMD),以计算消化能(DE)和代谢能(ME),并根据预测干物质随意采食量(DMI),进而计算出分级指数(GI)。结果表明,不同粗饲料间的常规养分的差异不能准确地评价饲料营养价值;以NDF、ADF所得GI综合评价粗饲料中营养价值得到苜蓿>冬牧70>地瓜秧>羊草>花生秧>青贮玉米秸>玉米秸>水稻秸>豆秸>麦秸;IVDMD与NDF、ADF均呈显著负相关,而与CP呈显著正相关;DE与NDF、ADF相关性较强,且均呈负相关。     

Fibre analysis and fibre digestibility in pet foods--a comparison of total dietary fibre, neutral and acid detergent fibre and crude fibre

Six dry dog foods and six dry cat foods with different carbohydrate sources were investigated in digestion trials. Food and faecal samples were analysed for CF, TDF and starch. In dogs, also neutral detergent fibre (aNDFom) and acid detergent fibre (ADFom) were analysed. N-free extract (NfE) was calculated for CF, and similarly for all other fibre analyses. Linear regressions were calculated between fibre intake and faecal fibre excretion. True digestibility was calculated from the regression coefficients [true digestibility in % = (1 - regression coefficient)*100], with the intercept of the equation representing excretion of material of non-food origin. Crude fibre analyses gave the lowest values, and TDF the highest, while ADFom and aNDFom were in between. Variation between diets was lowest in CF and highest in TDF. Total dietary fibre, aNDFom and ADFom in food were positively correlated. Crude fibre in food did not correlate with any other method. The NfE analogue for TDF was closest to the starch content. Methods of fibre analyses in faeces did not agree very well with each other. Crude fibre had the lowest apparent digestibility, followed by ADFom, TDF and aNDFom. For all fibre analyses, there was a significant correlation between fibre intake and faecal fibre excretion. True digestibility was close to zero for CF, with a high uniformity in both species. In dogs, true digestibility of aNDFom was 53%, of ADFom 26% and of TDF 37%; in cats, true digestibility of TDF was 31%. Except for CF, the intercept of the regression equations suggest that faecal excretion of some material of non-food origin is analysed as fibre. A combination of TDF and CF analyses might give good information on the content of total (TDF), unfermentable (CF) and partially fermentable fibre (TDF-CF) in pet foods.     

生长前期丝羽乌骨鸡饲粮适宜能量、蛋白水平研究

两因子设计 ,以1日龄丝羽乌骨鸡504只为材料 ,进行饲养试验结合代谢试验考察了饲粮代谢能(ME)、粗蛋白质(CP)对生长前期(0～8周)丝羽乌骨鸡生产性能的影响规律。结果表明 ,通过饲粮营养调控可显著改善生长前期丝羽乌骨鸡的生长速度和生产性能 ,ME显著(P<0.05)或极显著(P<0.01)影响各阶段平均日采食量(ADFI)和饲料转化率(FCR) ,CP显著影响3周龄前的生产性能指标(P<0.05) ,二者互作影响不显著(P>0.05) ;增加营养素摄入量有利于改善丝羽乌骨鸡对营养素的表观利用率。推荐3周龄前饲粮ME为13.40MJ/kg、CP为20 % ,整个生长前期(0～8周)推荐使用ME为12.35MJ/kg、CP为18 %饲粮以获得较好生产成绩和经济效益