Digestible Energy Intake Research Articles

Grazing camels under semi-extensive production system: selectivity, feed intake capacity, digestion and energy expenditure

BackgroundIt was proposed that camels are more effective than other livestock species in selecting plants for their nutritional value. They may self-regulate their voluntary feed intake to satisfy their nutritional needs. This study was designed to investigate camels’ feeding selectivity and ability to cover nutritional requirements when grazing alfalfa (high in protein) and/ or barley (high in energy) in a desert climate.MethodsEighteen lactating camels were equally divided into three feeding treatments. They grazed daily on alfalfa, barley, or a mixed pasture of both, for two periods of one month each. The concentrate supplement was individually administered at 40 g/kg BW0.75, divided into two equal parts, in the morning and in afternoon. Total energy expenditure (EE) was estimated by heart rate (HR) monitors for 48 h after being calibrated by oxygen consumption using an upgraded face mask open-circuit respiratory system.ResultsDuring the first period, camels had a greater forage intake and digestibility when they grazed barley rather than alfalfa, while those grazing mixed pasture performed intermediately. In the second period, camels had a similar forage intake and digestibility among treatments due to a decline in barley intake and digestibility compared to the first period, which was expected since the preferred plant part gradually shifted from barley grains to predominantly straw as a function of time. Similar HR and EE were found across periods and treatments. As a result of greater gross and digestible energy intake in period 1, a better energy balance in period 1 was observed compared to period 2. Camels better utilize barley than alfalfa. Grazing on barley had a higher energy balance than grazing alfalfa alone or in combination with barley. However, camels grazing barley produced lower milk yield and energy than those grazing alfalfa alone or in combination with barley, with no interaction detected between period and treatment.ConclusionsLactating camels are able to self-regulate their voluntary intake to cover their energy requirements when they are grazing barley and/or alfalfa supplemented with a concentrate supplement at 40 g/kg BW0.75. Grazing barley is better utilized by camels than alfalfa. The chemical and physical properties of plant species play an important role in the selectivity of foraging camels. It also impacts their intake and digestibility, which is negatively associated with the proportion of cell wall content consumed.

Substituting effects of winged bean tuber-modified starches for cassava chip in concentrate diets on rumen fermentation, nutrient utilization, and blood metabolites in Thai native beef cattle.

This study examined the effects of substituting winged bean tuber steam (WBTS) modified starches for cassava chips (CSC) in the concentrate diet on rumen fermentation, nutrient utilization, and blood metabolites in Thai-native beef cattle. Four Thai-native bulls were assigned randomly as a 4×4 Latin square design, which represents the amount of CSC replaced with WBTS in the concentrate mixture diets at 0%, 10%, 20%, and 30%. Increasing levels of WBTS replacement for CSC in the concentrate diets had a quadratic effect on total dry matter (DM) intake (p<0.05). Replacement of WBTS at 20% and 30% for CSC did not alter total DM intake compared to 0% WBTS, whereas 10% WBTS replacement could significantly increase total DM intake by 0.41 kg DM/d compared to the control group. In addition, neutral detergent fiber (NDF) digestibility showed a quadratic increase (p<0.05) when CSC was substituted at various levels of WBTS in the concentrate diet (p<0.05). Replacement of CSC with WBTS at 10% and 20% showed higher NDF digestibility when compared to 0% replacement. There was a quadratic increase in blood glucose at 4 h post-feeding, and the average blood glucose value was significantly lower (p<0.01) when substituting CSC with WBTS. Substituting WBTS for CSC at 10% in the concentrate diet showed the highest blood glucose concentration when compared to other treatments. Replacing CSC with WBTS at 10% and 20% shows a higher concentration of C3 than those of other treatments (0% or 30%). The nitrogen (N) intake increased linearly (p<0.05) when substituting WBTS for CSC at all levels in the diet. Additionally, N retention and the ratio of N retention to N intake increased (p<0.05) when substituting WBTS for CSC at 10%, 20%, and 30% compared to 0%. The gross energy intake (GEI), digestible energy intake (DEI), and energy efficiency (DEI/GEI) were quadratically increased when substituted with various levels of WBTS for CSC in the concentrate diet. The findings indicate that substituting 10% of CSC in the concentrate diet with WBTS may be sufficient as an alternative feed resource for improving nutrient utilization and metabolic efficiency in beef cattle diets.

Effect of feeding Bengal gram residual forage-based pelleted total mixed ration on growth performance, nutrient availability, carcass traits and composition in finisher Barbari kids.

The study aimed to assess the impact of feeding Bengal gram residual forage-based pelleted Total Mixed Ration (TMR) with varying concentrate (C) to roughage (R) ratios on feed intake, nutrient utilization, growth, and carcass characteristics in Barbari kids. Sixteen weaned male Barbari kids (av. age, 233 ± 11 days; weight, 13.86 ± 0.76kg) were divided into two groups (T1 and T2), each receiving different pelleted diets (TMR) with distinct concentrate to roughage ratios (T1 with 60:40; T2 with 40:60). The kids were fed for 133 days, and a digestion trial was conducted at the end of the study. After completion, all kids were slaughtered. Although, kids under T1 consumed higher (P < 0.001) amount of dry matter, and crude protein compared to T2, which was due to a higher concentrate to roughage ratio in T1. But, the average daily body weight gain (ADG) of finisher kids was 88.53, and 79.83g/d/kid in T1 and T2, respectively; however, the difference was non-significant. Digestibility of organic matter, crude protein, and total carbohydrate was also greater in T1 compared to T2. Total digestible nutrients intake was higher (P < 0.001) in T1; similarly intake of digestible energy, and metabolizable energy were significantly increased (P < 0.01) in T1 compared to T2. Concentrations of volatile fatty acids and NH3-nitrogen were also enhanced (P < 0.05) in T1 compared to T2. We observed similar carcass weight, and dressing percentage in both groups, and carcass composition remained unaffected. The pelleted diet containing greater ratio of concentrate: roughage (60:40) had no additional benefits in terms of ADG, and carcass traits in finisher kids. Therefore, it may be concluded that the Bengal gram residual forage-based pelleted TMR diet containing C40: R60 (TDN 57.13%, DCP 7.64%, ME 9.11MJ/kg feed) is suitable for optimizing growth performance with desirable carcass traits, and meat composition in finisher Barbari kids reared under the intensive system.

A meta-analysis of the relationship between milk protein production and absorbed amino acids and digested energy in dairy cattle

Milk protein production is the largest draw on AA supplies for lactating dairy cattle. Prior NRC predictions of milk protein production have been absorbed protein (MP)-based and used a first-limiting nutrient concept to integrate the effects of energy and protein, which yielded poor accuracy and precision (root mean squared error [RMSE] >21%). Using a meta-data set gathered, various alternative equation forms considering MP, absorbed total EAA, absorbed individual EAA, and digested energy (DE) supplies as additive drivers of production were evaluated, and all were found to be superior in statistical performance to the first limitation approach (RMSE = 14%-15%). Inclusion of DE intake and a quadratic term for MP or absorbed EAA supplies were found to be necessary to achieve intercept estimates (nonproductive protein use) that were similar to the factorial estimates of the National Academies of Sciences, Engineering, and Medicine (2021). The partial linear slope for MP was found to be 0.409, which is consistent with the observed slope bias of -0.34 g/g when a slope of 0.67 was used for MP efficiency in a first-limiting nutrient system. Replacement of MP with the supplies of individual absorbed EAA expressed in grams per day and a common quadratic across the EAA resulted in unbiased predictions with improved statistical performance as compared with MP-based models. Based on Akaike's information criterion and biological consistency, the best equations included absorbed His, Ile, Lys, Met, Thr, the NEAA, and individual DE intakes from fatty acids, NDF, residual OM, and starch. Several also contained a term for absorbed Leu. These equations generally had RMSE of 14.3% and a concordance correlation of 0.76. Based on the common quadratic and individual linear terms, milk protein response plateaus were predicted at approximately 320 g/d of absorbed His, Ile, and Lys; 395 g/d of absorbed Thr; 550 g/d of absorbed Met; and 70 g/d of absorbed Leu. Therefore, responses to each except Leu are almost linear throughout the normal in vivo range. De-aggregation of the quadratic term and parsing to individual absorbed EAA resulted in nonbiological estimates for several EAA indicating over-parameterization. Expression of the EAA as g/100 g total absorbed EAA or as ratios of DE intake and using linear and quadratic terms for each EAA resulted in similar statistical performance, but the solutions had identifiability problems and several nonbiological parameter estimates. The use of ratios also introduced nonlinearity in the independent variables which violates linear regression assumptions. Further screening of the global model using absorbed EAA expressed as grams per day with a common quadratic using an all-models approach, and exhaustive cross-evaluation indicated the parameter estimates for BW, all 4 DE terms, His, Ile, Lys, Met, and the common quadratic term were stable, whereas estimates for Leu and Thr were known with less certainty. Use of independent and additive terms and a quadratic expression in the equation results in variable efficiencies of conversion. The additivity also provides partial substitution among the nutrients. Both of these prevent establishment of fixed nutrient requirements in support of milk protein production.

149 Using respiratory gas flux and backward dietary energy partitioning to estimate energy intake by beef cattle fed a high concentrate diet

Abstract Twelve Charolais steers (BW = 498 ± 47.4 kg) were used in a 73-d feeding experiment. Our objective was to determine if CH4 and CO2 emissions, and O2 consumption could be used as biomarkers to estimate energy intake in growing beef cattle when integrated with backward dietary energy partitioning calculations when fed a high concentrate diet. Steers were housed in a pen equipped with individual feed bunks with access to an automated head chamber system (AHCS; GreenFeed, C-Lock, Inc., Rapid City, SD). Steers were randomly assigned to 1 of 3 treatments according to DMI as multiple of maintenance, which are 1.1 (1.1 M, n = 4), 1.4 (1.4 M, n = 4), and 1.8 (1.8 M, n = 4). The diet fed was 35% chopped sorghum hay (CP = 6.39% of DM; in vitro OM digestibility = 57.77%) and 65% concentrate (CP = 19.10% of DM; in vitro OM digestibility = 91.84%). The concentrate consisted of 41.75% flaked corn, 8.5% cottonseed meal, 13% distillers’ grain and 1.75% limestone. Steers were supplemented daily with 0.85 kg of alfalfa pellets (Medicago sativa; CP= 16.55%; in vitro OM digestibility = 87.01%) that were fed through the AHCS as bait. Methane tended (P = 0.09) and CO2 emissions and O2 consumption (P &amp;lt; 0.01) increased with the increasing feeding rates. Measured gross energy (GE; 21.9, 24.8, 29.5 Mcal/d, respectively), digestible energy (DE; 19.7, 22.0, 25.8 Mcal/d, respectively), and metabolizable energy (ME; 17.2, 19.2, 22.7 Mcal/d, respectively) intake levels increased with the increases in energy retention and heat production. The predicted values for GE (17.4, 23.6, 28.2 Mcal/d), DE (15.1, 20.8, 24.4 Mcal/d), and ME (12.6, 17.9, 21.3 Mcal/d) intake rates increased with the increase from 1.1 M to 1.8 M. Comparison of measured and predicted GE, DE, and ME intake rates agreed closely (r = 0.95, 0.93, 0.92 Pearson correlation, respectively). This experiment shows that together with multiple short-term breath measurements from an AHCS, BW, and an estimate of average daily gain, GE, DE, and ME intakes by cattle consuming a high concentrate diet can be predicted.

Development of dynamic growth and body composition models for Nile Tilapia (Oreochromis niloticus): An exploratory approach to protein and energy metabolism

The aquaculture sector has been steadily growing and thus there is an increasing need to develop mathematical models that allow the estimation of production-related parameters. Prediction of fish growth, feed requirements and waste outputs, are essential in order to ensure the profitability and sustainability of the production activities. Bioenergetic models have been widely used to estimate growth based on energy budgets, but they have some limitations by not explicitly considering the mass-balance of the main macronutrients (e.g., protein). In turn, nutrient-based models are more explanatory, as they consider both energy and nutrient inputs, and estimate fish growth by simulating nutrient accumulation in the fish body. Although some bioenergetic and nutrient-base models for predicting Nile tilapia growth exist in the literature, their suitability is not entirely clear, since their development is often based on uncertain or suboptimal criteria (e.g., relying solely on calibration goodness-of-fit measures).In this work, Nile tilapia growth datasets covering a wide range of rearing conditions and feed compositions were collected from the scientific literature. An exploratory analysis of the collected data was performed to clarify the relationships between energy/protein intake and gain. In this analysis, a direct relationship was observed between digestible energy intake and energy gain, as well as between digestible protein intake and protein gain. Protein gain showed better efficiency than energy gain, even at higher intake levels and without clear evidence of a saturation effect. While digestible energy intake negatively affects energy retention efficiency, digestible protein intake does not significantly impact protein retention efficiency. Furthermore, while energy retention efficiency varies with fish body weight, the same effect was not observed for protein retention efficiency. Finally, though DP/DE ratio has no apparent effect on energy retention efficiency, it seems to negatively affect protein retention efficiency. Considering these observations, plausible growth models with different levels of complexity were developed and calibrated under a diverse set of assumptions. Additionally, two growth models already published for Nile tilapia were calibrated using the same datasets, and their performance was compared with the models developed in the present study. The exploratory analysis of the data suggests a direct relationship between digestible energy intake and energy gain, and between digestible protein intake and protein gain. Furthermore, fish body weight seems to affect the energy retention efficiency. The results of model evaluation showed that energy-protein flux models (EP models) have lower errors in predicting fish growth than pure bioenergetic models (MAPEbw ∼ 9% against ∼13%, respectively), showing the importance of considering protein intake when estimating Nile tilapia growth. Furthermore, assuming the fixed standard metabolic body weight exponents of 0.80 and 0.70 (for energy and protein, respectively), rather than estimating them from the data, seemingly improved the predictive ability of the models. This approach demonstrates the benefits of coupling bioenergetics with nutrient-based models to predict growth and body composition of Nile tilapia along time.

Effect of temperature on the energy utilization efficiencies of digested protein, fat, and carbohydrates in Nile tilapia (Oreochromis niloticus)

Most effective feed formulations for fish have historically relied mainly on digestible energy (DE) but recently also on net energy (NE) approaches, which indicate how energy or macronutrients are utilized for growth or energy retention (RE). This study aimed to determine the effect of temperature on 1) DE-based feed formulations that explored the relationship between DE intake and RE, and 2) NE-based feed formulations that examined the energy utilization efficiency of macronutrients, specifically digested protein (dCP), fat (dFat), and carbohydrate (dCarb) for growth in Nile tilapia. The study involved two separate experiments, one at 24 °C and one at 32 °C for Nile tilapia (initial weight ∼ 38 g). Four diets having contrasting levels of protein, fat, and carbohydrates were used; and two feeding levels (FL; 10 vs. 18 g.kg−0.8.d−1) were applied. Digestibility of protein differed more between FLs at 32 °C. In contrast, fat and carbohydrate digestibility differed more between FLs at 24 °C. The slope of the relationship of RE to DE intake differed between 24 and 32 °C at one of the four diets (P < 0.05), which implies that the DE value of diets/ingredient is dependent on temperature. RE was related to dCP, dFat, and dCarb intake at 24 °C as RE = −27.6 (SE 2.86) + 13.3 (SE 0.53) dCP + 32.0 (SE 0.81) dFat +10.9 (SE 0.43) dCarb, R2 = 0.99 and at 32 °C as RE = −54.4 (SE 5.43) + 14.7 (SE 0.96) dCP + 32.7 (SE 1.46) dFat +10.6 (SE 0.77) dCarb, R2 = 0.98. Fasting heat production increased with temperature (27.6 vs. 54.4 kJ.kg−0.8.d−1; P < 0.05). The energy utilization efficiencies of dCP, dFat, and dCarb were similar at 24 and 32 °C (P > 0.05); being 56, 81, and 63% at 24 °C and 62, 83, and 62% at 32 °C. The practical implication of this is that the NE approach of feed evaluation for Nile tilapia is independent of water temperature.

Review: How the efficiency of utilization of essential amino acids can be applied in dairy cow nutrition.

How the efficiency of utilization of essential amino acids (EffUEAA) can be applied in dairy cow nutrition is presented in this review. The concept of EffUEAA proposed by the National Academies of Sciences, Engineering and Medicine (NASEM, 2021) is first detailed. It represents the proportion of the metabolisable essential amino acids (mEAA) supply used to support protein secretions and accretions (scurf, metabolic fecal, milk and growth). For these processes, the efficiency of each individual EAA is variable, and considered to vary similarly for all the protein secretions and accretions. The anabolic process of gestation is ascribed to a constant efficiency (33%), whereas the efficiency of endogenous urinary loss (EndoUri) is set at 100%. Therefore, the NASEM model EffUEAA was calculated as the sum of EAA in the true protein of secretions and accretions divided by the available EAA (mEAA - EndoUri - gestation net true protein/0.33). In this paper, the reliability of this mathematical calculation was tested through an example where the experimental efficiency of His was calculated assuming that liver removal represents catabolism. The NASEM model and experimental efficiencies were in the same range and varied in similar manner. Assuming that the NASEM model EffUEAA reflects EAA metabolism in the dairy cow, its different applications were examined. In NASEM, target efficiencies were determined for each EAA: 75, 71, 73, 72, 73, 60, 64, 86 and 74% for His, Ile, Leu, Lys, Met, Phe, Thr, Trp, and Val, respectively. From these, recommendations for mEAA supply can be calculated as: [(secretions + accretions)/(target EffUEAA×0.01)+EndoUri+gestation/0.33], assuming energy supply is adequate. In addition to NASEM propositions, equations to predict EffUEAA with precision and accuracy are detailed, using the ratio of (mEAA-EndoUri) to digestible energy intake, in a quadratic model that includes days in milk. Moreover, milk true protein yield predictions from predicted EffUEAA or efficiency of utilization of metabolisable protein are better than those from the multivariate equation of NASEM (2021) and superior to those predicted with a fixed efficiency. Finally, either the NASEM model or the predicted EffUEAA can be used to assess the responsiveness of a ration to supplementation with a single EAA. If the EffUEAA of the EAA to supplement is higher than the target EffUEAA, while the EffUEAA of the other EAA are lower than the target value, this suggests a potential improvement in milk true protein yield to supplementation with this EAA.

79 Investigation of body condition scores, feedstuff, and feed intake in a racing pony population in West Nusa Tenggara

A healthy body condition is essential for equine health and performance. Therefore, recognizing equine body condition and adjusting nutritional management are required for the best output. This study aimed to determine: 1) general feeding practice and desired body condition scores (BCS) by the owners, 3) body condition scores and morphometric measurements, and 2) feedstuffs used and estimated nutritional intake, of racing ponies in West Nusa Tenggara, Indonesia. An online initial survey form was sent to the farmers via Whatsapp and Facebook groups. The form also included a list of pictures of ponies with different BCS. Owners were asked if the ponies in the pictures were ideal for racing purposes. Fifty-two pony owners filled in the survey and 21 owners of 54 ponies that actively raced signed up for the next part of the study. The ponies’ age was 3.6 ± 3.6 years. Meanwhile, the breeds consisted of 37% (20/54) Sumbawa ponies, 25.9% (14/54) Sandalwood-cross ponies, 20.4% (11/54) Sandalwood ponies, 11.1% (6/54) Flores ponies, and 3.7% (2/54) Lombok ponies. Ponies were accessed, BCS and cresty neck scores (CNS) were assessed, and morphometric parameters were measured. These were also used to estimatebodyweight. Feeds were weighed, identified and sent for nutritional analysis. Owners’ answers indicated that they were aware of the importance of nutrition and proper body conditions for their ponies. Moreover, the highest agreement on how ideal a pony for racing was on a pony with BCS 5.5. Furthermore, mean BCS of ponies signed up for this study was 5.16 ± 0.5 (out of 9). The most commonly fed forage species were Cynodon dactylon, Leersia hexandra, and Eulalia aurera, with rice bran as the main concentrate. Mean DE intake was ∼1 Mcal above NRC recommendation. Mean protein intake was 19% higher than NRC recommendation. Calcium intake was below NRC recommendation with phosphorus intake above NRC recommendation. The calcium: phosphorus ratio was concerning as phosphorus intake was 5 times calcium intake. Finally, owners’ answers (21/21) indicated that they would need educational materials about equine nutrition, particularly on feeding balanced diets for the animals.

Replacing ground corn with soyhulls plus palmitic acid in low metabolizable protein diets with or without rumen-protected amino acids: Effects on production and nutrient utilization in dairy cows

We previously observed that diets with reduced starch concentration decreased yields of milk and milk protein in dairy cows fed low metabolizable protein diets. Supplementation of reduced-starch diets with a lipid source may attenuate or eliminate production losses. Our objective was to investigate the effects of partially replacing ground corn with soyhulls plus a palmitic acid-enriched supplement on dry matter (DM) intake, milk yield and composition, plasma AA concentration, and N and energy utilization in cows fed low metabolizable protein diets (mean = -68 g/d balance) with or without rumen-protected Met, Lys, and His (RP-MLH). Sixteen multiparous Holstein cows averaging (mean ± standard deviation) 112 ± 28 d in milk, 724 ± 44 kg of body weight, and 46 ± 5 kg/d of milk in the beginning of the study were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Each period lasted 21 d, consisting of 14 d for diet adaptation and 7 d for data and sample collection. Diets were fed as follows: (1) high starch (HS), (2) HS plus RP-MLH (HS+AA), (3) reduced starch plus a palmitic acid-enriched supplement (RSPA), and (4) RSPA plus RP-MLH (RSPA+AA). The HS diet contained (DM basis) 26% ground corn and 7% soyhulls, and the RSPA diet had 10% ground corn, 22% soyhulls, and 1.5% palmitic acid. The HS diet averaged (DM basis) 32.6% starch and 4% ether extract, while starch and ether extract concentrations of the RSPA diet were 21.7 and 5.9%, respectively. All 4 diets had (DM basis) 40% corn silage, 5% mixed-mostly grass haylage, 5% grass hay, and 50% concentrate. Diets did not affect DM intake and milk yield. Contrarily, feeding RSPA and RSPA+AA increased yields of energy-corrected milk (47.0 vs. 44.8 kg/d) and milk fat (1.65 vs. 1.50 kg/d) compared with HS and HS+AA. Milk fat concentration tended to decrease when RP-MLH was supplemented to HS, but no change was seen when added to RS (starch level × RP-MLH interaction). Milk and plasma urea N increased, and milk N efficiency decreased in cows fed RSPA and RSPA+AA versus HS and HS+AA. Apparent total-tract digestibilites of crude protein and neutral detergent fiber, as well as urinary urea N and total N excretion, were greater in cows offered RSPA and RSPA+AA than HS and HS+AA. Plasma Met and His concentrations increased with supplemental RP-MLH. Intake of gross energy and digestible energy and the output of urinary and milk energy were all greater with feeding RSPA and RSPA+AA versus HS and HS+AA. In summary, partially replacing ground corn with soyhulls plus palmitic acid in diets supplemented or not with RP-MLH increased milk fat yield and fiber digestibility and maintained DM intake and milk yield, but with decreased milk N efficiency and elevated urinary N excretion.

Effect of exogenous fibrolytic enzymes supplementation on voluntary intake, availability of nutrients and growth performance in Black Bengal kids (Capra hircus)

A Growth experiment was conducted on fifteen weaned Black Bengal kids divided into three groups. Kids under control (T0) group were fed ad libitum Total Mixed Ration (TMR) prepared from concentrate mixture and green fodder @ 40: 60 (on a DM basis). Kids under T1 and T2 groups were supplemented with two levels of EFE (T1 with cellulase and xylanase @ 8000 and 16,000IU/kg TMR DM and T2 with 12,000 and 24,000IU/kg TMR DM). A digestion trial was also conducted during the last phase of the growth trial. The intake of nutrients, like DM, OM, CP, TDN, and DCP (g/kg W0.75) were significantly (P < 0.001) higher in enzyme-supplemented treatments. Supplementation of EFE also increased (P < 0.001) intake of DE and ME (Mcal/ kg W0.75) in Black Bengal kids. The differences in all the blood biochemical parameters and enzymes (glucose, total protein, globulin, albumin, urea, AST, and ALT) were non-significant (P > 0.05) among the three treatment groups. Average daily body weight gain (ADG, g/d/kid) was increased significantly (P < 0.05) by 7.00 % in T1 and 7.19 % in T2 over the control group (T0). The FCE (feed conversion efficiency) was also greater (P < 0.05) in both enzyme-supplemented (T1 and T2) groups compared to the control. The results depicted no additional advantage due to the supplementation of a higher level of an enzyme mixture. Therefore, it may be concluded that the supplementation of EFE @ cellulase 8000 and xylanase 16,000IU/kg diet DM increased the intake of different nutrients and growth performance in weaned Black Bengal kids.

Predicting microbial crude protein synthesis in cattle from intakes of dietary energy and crude protein.

Accurate predictions of microbial crude protein (MCP) synthesis are needed to predict metabolizable protein supply in ruminants. Since 1996, the National Academies of Sciences, Engineering, and Medicine series on beef cattle nutrient requirements has used the intake of total digestible nutrients (TDN) to predict ruminal MCP synthesis. Because various tabular energy values for feeds are highly correlated, our objective was to determine whether intakes of digestible energy (DE), metabolizable energy (ME), and net energy for maintenance (NEm) could be used as predictors of MCP synthesis in beef cattle. A published database of 285 treatment means from experiments that evaluated MCP synthesis was updated with 50 additional treatment mean observations. When intakes of TDN, fat-free TDN, DE, ME, NEm, dry matter, organic matter, crude protein (CP), ether extract, neutral detergent fiber, and starch were used in a stepwise regression analysis to predict MCP, only intakes of DE and CP met the P < 0.10 criterion for entry into the model. Mixed-model regression analyses were used to adjust for random intercept and slope effects of citations to evaluate intake of DE alone or in combination with CP intake as predictors of MCP synthesis, and the intakes of TDN, ME, and NEm as alternatives to DE intake. Similar precisions in predicting MCP synthesis were obtained with all measures of energy intake (CV = root mean square error [RMSE] as a percentage of the overall mean MCP varied from 9% to 9.67%), and adding CP intake to statistical models increased precision (CV ranged from 8.43% to 9.39%). Resampling analyses were used to evaluate observed vs. predicted values for the various energy intake models with or without CP intake, as well as the TDN-based equation used in the current beef cattle nutrient requirements calculations. The coefficient of determination, concordance correlation coefficient, and RMSE of prediction as a percentage of the mean averaged 0.595%, 0.730%, and 28.6% for the four measures of energy intake, with average values of 0.630%, 0.757%, and 27.4%, respectively, for equations that included CP intake. The TDN equation adopted by the 2016 beef cattle nutrient requirements system yielded similar results to newly developed equations but had a slightly greater mean bias. We concluded that any of the measures of energy intake we evaluated can be used to predict MCP synthesis by beef cattle and that adding CP intake improves model precision.

PUFA supplements to improve diarrhea, fecal consistency, and disease resilience in neonatal and preweaning calves

The flaxseed oil (FSO) rich in polyunsaturated fatty acids (PUFA) were supplemented orally to ten male and female neonatal calves from day 6 of birth to day 28 to improve resilience to disease incidences (TG) and compared to calves reared without PUFA supplement (CG). The PUFA supplementation in liquid form was discontinued on day 29 and fed as bolus consisting of 25 g of ground flaxseed and 25 g of jaggery until day 90. The total dry matter intake in cluding milk solids in neonata calves was 400 g in CG and 428 g in TG (P=0.38). Digestible DMI, CP and energy intake in male and female calves of TGs was significantly (P&lt; 0.05) higher the CG. However, the body weight gain in calves during neonatal (P=0.08) and preweaning (P=0.14) age was comparable between groups. The serum IgG were 30 mg/mL on day 2 but higher in calves in TGs on day 7 (P=0.08) and day 14 (P=0.07)after birth but comparable in subsequent period until day 30 after birth. Calves resilience to diarrhea, pyrexia, anorexia, skin infection, profused lacrimation, navel ill, muzzle keratinization, umbilical hernia, fecal consistency (FC), and egg count (FEC) were examined. PUFA supplementation reduced the disease risk rate in TG by 42% (P&lt; 0.001) and diarrhea by three folds compared to CG. Haemoglobin, erythrocytes, and lymphocytes improved significantly from day 30 after birth. The intervention was recommended to reduce calf mortality and imrpoved health and body weight gain during neonatal and preweaning age.

Açai seed as an additive in Panicum maximum cv. Mombasa ensiling for ruminant nutrition: An alternative to reduce environmental pollutants

The objective of this study was to evaluate the potential use of açai ( Euterpe oleracea ) seeds as a moisture sequestrant in Panicum maximum cv. Mombasa grass silage and its potential use in sheep diet. In this study, we conducted two experiments using Mombasa grass silage supplemented with açai seeds at 0, 185, 225, 433, and 520 g.kg -1 dry matter (DM). Experiment 1 was used to evaluate the effect of açai seeds on DM, effluent loss (EL), chemical composition, and fermentation characteristics of the silage, while Experiment 2 was used to evaluate the effect of açai seeds on the intake, digestibility, and nitrogen (N) balance of the sheep fed açai seed-supplemented Mombasa grass silage. In Experiment 1, the DM content of the silages increased, and the EL decreased with an increase in the açai seed concentration ( P <0.05). In Experiment 2, the DM, organic matter, crude protein, and neutral detergent fiber intake increased ( P <0.05), while the digestible energy intake and N balance were unaffected ( P >0.05) with increasing açai seed concentration in the silage. Açai seeds, up to 520 g.kg -1 DM inclusion level, are effective moisture sequestrants in the Mombasa grass silage because they reduce EL, increase the DM recovery of the ensiled material, and increase the DM intake of the animals. Furthermore, the use of açai seeds as additives in silage is beneficial to the environment because of the reduction in waste production from the açai pulp processing and subsequent reduction in the generation of effluents from silage. • The use of açai seed reduces the effluent generated from silage • Açai seeds increase the dry matter recovery of the ensiled material • The sheep nitrogen retention does not change with açai seed inclusion in the silage • The sheep energy intake does not change with açai seed inclusion in the silage

Seasonal adjustments in body mass and basal thermogenesis in Chinese hwameis (Garrulax canorus): the roles of temperature and photoperiod.

For small birds to survive during seasonal acclimatization in temperate zones, regulation of body mass and thermogenesis is crucial. To determine the role of temperature and photoperiod in seasonal changes in body mass and thermogenesis in Chinese hwameis (Garrulax canorus), we compared body mass, basal metabolic rate (BMR), energy intake and cellular metabolic capacity of the tissue (muscle) and/or organs (liver, kidney, heart and small intestine) in seasonally acclimatized and laboratory-acclimated hwameis. A significant seasonal influence on body mass and BMR (which peaked in winter) was found, and these variations were mirrored by exposing the housed birds to cold temperatures or a short photoperiod. The level of dry matter intake, gross energy intake and digestible energy intake was higher during winter, and in housed animals that were exposed to cold temperatures. These results suggest that by increasing energy intake and thermogenesis, Chinese hwameis can overcome winter thermoregulatory challenges. When compared with warm-acclimated birds, cold-acclimated birds displayed higher mass-specific and whole-organ state 4 respiration in the muscle, liver and kidney, and higher mass-specific and whole-organ cytochrome c oxidase activity in the liver. These data demonstrate that cellular thermogenesis partly underpins basal thermoregulation in Chinese hwameis. Cold temperature and short photoperiod can be used as helpful environmental cues during seasonal acclimatization. However, the role of temperature is more significant compared with that of photoperiod in Chinese hwameis; the changes in energy metabolism and thermoregulation induced by temperature appear to be intensified by photoperiod.

Effects of Dietary Inclusion of Sericea Lespedeza Hay on Feed Intake, Digestion, Nutrient Utilization, Growth Performance, and Ruminal Fermentation and Methane Emission of Alpine Doelings and Katahdin Ewe Lambs.

Simple SummaryRuminants contribute to global greenhouse gas production, mainly through enteric methane emission (EME). Different dietary strategies have been explored to mitigate EME, including the use of forages rich in tannins that inhibit methanogenic activity in the rumen. Feeding the condensed tannin-containing forage Sericea lespedeza (Lespedeza cuneata) has reduced EME by small ruminants in previous studies. In the present experiment, the digestion of fiber, and in particular of nitrogen, decreased as the concentration of lespedeza increased. Similar metabolizable energy intake and retained energy among diets suggests that decreasing digested nitrogen intake and protein status were responsible for marked declines in growth performance as the dietary amount of lespedeza increased. In contrast to many other reports, the dietary concentration of lespedeza did not affect EME by goats or sheep under these feeding conditions.Twenty-four Alpine doelings, initial 25.3 ± 0.55 kg body weight (BW) and 10.4 ± 0.11 mo of age, and 24 Katahdin ewe lambs, 28.3 ± 1.02 kg BW and 9.6 ± 0.04 mo of age, were used to determine effects of dietary inclusion of Sericea lespedeza (Lespedeza cuneata) hay on feed intake, digestion, growth performance, energy metabolism, and ruminal fermentation and methane emission. There were four periods, the first three 42 days in length and the fourth 47 days. Diets consumed ad libitum contained 75% coarsely ground hay with alfalfa (ALF), a 1:1 mixture of ALF and LES (ALF+LES), and LES (10.0% condensed tannins; CT). The intake of dry matter (DM) tended to be greater (p = 0.063) for Katahdin than for Alpine (4.14 vs. 3.84% BW; SEM = 0.110). The dry matter intake was similar among the diets (3.97, 4.10, and 3.89% BW for ALF, ALF+LES, and LES, respectively; SEM = 0.134). The digestion of organic matter (75.3, 69.3, and 65.5%; SEM = 0.86), neutral detergent fiber (61.7, 50.5, and 41.4%; SEM = 1.49), and nitrogen (78.8, 66.9, and 50.8% for ALF, ALF+LES, and LES, respectively; SEM = 0.92) decreased as the dietary concentration of lespedeza increased (p < 0.05). However, there was an interaction (p < 0.05) between the breed and diet in nitrogen digestion, with a greater value for goats vs. sheep with LES (54.4 vs. 47.3%; SEM = 1.30). The digested nitrogen intake decreased markedly with the increasing quantity of lespedeza (38.0, 27.5, and 15.7 g/day for ALF, ALF+LES, and LES, respectively; SEM = 1.26). The average daily gain was greater for Katahdin than for Alpine (p < 0.001; 180 vs. 88 g, SEM = 5.0) and ranked (p < 0.05) ALF > ALF+LES > LES (159, 132, and 111 g, respectively; SEM = 6.1). The ruminal methane emission differed (p < 0.05) between animal types in MJ/day (1.17 and 1.44), kJ/g DM intake (1.39 and 1.23), and kJ/g ADG (18.1 and 9.8 for Alpine and Katahdin, respectively). Regardless of the period and animal type, diet did not impact methane emission in MJ/day or relative to DM intake, BW, or ADG (p > 0.05). The digestible and metabolizable energy intakes, heat production, and retained energy were not affected by diet (p > 0.05). In conclusion, future research should consider the marked potential effect of CT of forages such as lespedeza on nitrogen digestion and associated effects on protein status and other conditions that may be impacted.

Differences in energy utilisation between a lean and fat strain of rainbow trout (Oncorhynchus mykiss)

A good understanding of the utilisation of energy in fish diets is important for accurate feed formulation in aquaculture. One of the primary reasons for differences in the utilisation of digestible energy between fish species are differences that exist in the composition of growth (fat versus protein gain). However, it has also been observed that composition of growth can differ between genetic strains within a single fish species. The main focus of the current experiment was to investigate whether the genetic background of different strains of rainbow trout affects the relationship between digestible energy intake and retained energy. To test this, two different commercial trout strains were selected based on their differences in body fat content (a Lean-Strain and Fat-Strain) and therefore expected differences in composition of growth. Furthermore, this research investigated whether such a potential strain difference in the relationship between digestible energy and retained energy was dependent on the type of non-protein energy in the diet (a Carb-Diet versus a Fat-Diet). Three feeding levels were used in order to estimate the utilisation efficiency of digestible energy for retained energy, leading to a 2 by 2 by 3 factorial design. The results of this study showed that the relationship between digestible energy and retained energy was affected by both strain and diet, but not by an interaction effect between these two factors. Firstly, it was observed that the utilisation efficiency of digestible energy for growth (kgDE) was higher in the Fat-Strain (72% in the Lean-Strain versus 87% in the Fat-Strain) which may be related to a higher potential for fat deposition. This higher kgDE in the Fat-Strain was however balanced by a higher maintenance requirement (47 kJ/kg0.8 per day versus 28 kJ/kg0.8 per day) leading to a similar retained energy between strains in the current trial. Secondly, it was shown that the exchange of dietary carbohydrates for dietary fat on an isoenergetic basis also increased kgDE (74% for the Carb-Diet versus 85% for the Fat-Diet). The lack of an interaction effect between strain and diet showed that kgDE in both strains was affected by the exchange of carbohydrates for fat on an isoenergetic basis in a similar way. The results of the current trial demonstrated that both dietary macronutrient composition and the composition of growth of specific trout strains should be accounted for in calculating the true net available energy for fish in feed formulation.

Reduction of Enteric Methane Emissions in Heifers Fed Tropical Grass-Based Rations Supplemented with Palm Oil

Vegetable oils have been shown to reduce enteric methane (CH4) production by up to 20%. However, when the level of incorporation exceeds the threshold of 70 g/kg DM, dry matter intake (DMI) and nutrient digestibility may be reduced. The objective of this study was to determine the effects of the incorporation of three levels of palm oil (PO) on enteric CH4 emissions, rumen fermentation and apparent digestibility in heifers fed low-quality grass. Four rumen-cannulated heifers (Bos taurus × Bos indicus) were randomly assigned to four treatments: control (CON) and three increasing PO levels: 20, 40 and 60 g/kg in a 4 × 4 Latin square design with four periods of 22 days (14 days of adaptation to the ration), 5 days of feces and rumen fluid sampling (day 18, 4 h postprandial) and the last 3 days for measurements of CH4 in respiration chambers. With the exception of CP (p = 0.04), starch (p = 0.002) and EE (p &lt; 0.001), the intake of nutrients was not affected by the inclusion of PO (p &gt; 0.05). The apparent digestibility (AD) of nutrients was not affected by the inclusion of PO (p &gt; 0.05), except for starch, which reduced its AD as the PO level was increased (p &lt; 0.05). The gross energy intake was higher in PO-containing rations (p = 0.001), on the other hand, the digestible energy intake was similar between treatments (p &gt; 0.05). In situ ruminal digestion kinetics and the potential degradability remained unchanged (p &gt; 0.05), however, the effective degradability decreased with the inclusion of PO in the rations (p &lt; 0.05). The ruminal pH and molar proportions of acetic, isovaleric and valeric acid were not different between treatments (p &gt; 0.05). The ruminal concentration of propionic acid increased as the PO level increased, reaching its highest molar proportion with 60 g/kg PO (p &lt; 0.05), however, the acetic/propionic ratio and the molar proportions of butyric acid and isobutyric acid decreased as the PO level increased (p &lt; 0.05). The total daily CH4 production was lower in diets containing 20, 40 and 60 g/kg PO compared to the CON diet (p &lt; 0.001). The production of CH4 per kg DMI and DOMI was greater (p &lt; 0.05) for the CON diet compared to all three rations containing PO. The emission intensity, Ym, energy lost as CH4, emission factor (EF) and kg CO2 eq/year were reduced as an effect of the inclusion of PO (p &lt; 0.05). Based on the results obtained, it is concluded that the incorporation of PO in cattle rations has the potential to reduce enteric methane emissions by 4% for every 10 g/kg PO in the ration, without affecting DMI, apparent digestibility or the consumption of digestible nutrient fractions.

Average Daily Gain and Energy and Nitrogen Requirements of 4-Month-Old Female Yak Calves.

There is little information available on milk intake and energy and nitrogen requirements of growing yak calves. This study aimed to fill this important gap, as this information could be beneficial in designing a system to wean yak calves earlier than in natural time. We determined the average daily gain and energy and nitrogen balances and requirements of 4-month-old female yak calves (48.8 ± 2.45 kg, n = 8). The calves were allowed to suck once a day and were fed an ad libitum concentrate: hay diet at a ratio of 60:40. Milk intake averaged 540 ± 26 g/d, yielding 2.28 ± 0.112 MJ/d, which was 13% of the gross energy intake (GEI). The digestible energy intake (DEI):GEI ratio was 0.681, metabolizable energy intake (MEI):DEI was 0.913, and MEI:GEI was 0.621. The average daily gain of the calves was 433 ± 153.1 g/d, which consisted of 78.0 ± 8.99 g protein, 52.7 ± 23.74 g fat, and 302.3 ± 95.1 g water, that is, 18.0% protein, 13.0% fat and 69.8% water. There were 130.7 g of body solids and 9.06 MJ of energy in every kg of body mass gain. Of the MEI, 25.17 kJ were required for 1 g of body mass, 83.40 kJ for 1 g of body solids, and 2.62 kJ for 1 kJ of retained energy (RE), and RE was 36.6% of MEI. The maintenance energy requirement was 5.35 MJ/d, the efficiency of utilization of energy for growth (kg) was 0.72, and the heat increment of feeding for growth was 0.28 (1.55 MJ/d). Digestible nitrogen (N) was 0.685 while retained N (RN) was 0.489 of N intake. The N requirement for maintenance was 11.73 g/d or 0.61 g N/kg0.75 per day, while the biological value (BV) of N was 91.1%. The energy and N requirements for yak calves were relatively low, which could be explained, at least in part, by the high efficiency of utilization of energy and high BV of N when compared to other livestock. These findings could be beneficial in designing early weaning systems for the many Himalayan households depending on yak production for their livelihoods.

Effect of diet complexity and dietary fish peptide and enzyme complex supplementation on weanling pigs

Two experiments were conducted to assess the potential of replacing complex weanling pig diets with simple corn-soybean meal (SBM) diets by supplementation with a feed additive. The effort was made to determine the optimum inclusion rate of fish peptides in experiment 1 (Exp. 1), whereas the possibility of replacing complex diets with simply corn-SBM diets was investigated in Exp. 2. Ninety six (7.9 ± 0.7 kg) and 48 (7.8 ± 0.8 kg) pigs were used in Exp. 1 and 2, respectively, and pigs were assigned randomly to 6 (Exp. 1) and 3 (Exp. 2) dietary treatments with 4 pens per treatment and 2 gilts and 2 castrated males per pen in both experiments. The phase 1 (d 0 to 14) and 2 (d 14 to 28) complex, positive control diets (POS) were formulated in both experiments. Two simple corn-SBM, negative control (NEG) diets were formulated to be iso-lysinic to the POS diets in Exp. 1, and the NEG diets were supplemented with 0.5, 1.0, 1.5, or 2.0% fish peptides. Similarly, the phase 1 and 2 simple corn-SBM, NEG diets were formulated to be iso-lysinic to the POS diets in Exp. 2. However, the NEG diets contained 1.5% fish peptides, and those diets were supplemented with multienzyme complexes (ALL). During the wk 4, blood sample was collected and analyzed for serum metabolites and cytokines in Exp. 1 and metabolites in Exp. 2. During the last 2 wk of Exp. 1, the intake of feed, Lys, and digestible energy (DE) increased (cubic, P < 0.026) as fish peptides increased from 0 to 2%. Dietary treatments had no effect on gain to feed (G:F), gain to Lys (G:Lys), or gain to DE (G:DE) intake. Although there were some differences in serum total protein, urea N, and triglycerides, dietary treatments seemed to have no clear effect on serum metabolites or cytokines. Pigs seemed to respond to the diets containing 1.5% fish peptides, and it was used as the basis for the dietary treatments in Exp. 2. From wk 0 to 2 in Exp. 2, pigs fed the NEG and ALL diets had greater G:F, G:Lys intake, and G:DE intake (P < 0.004) than those fed the POS diet. In addition, G:F and G:Lys intake tended to be greater (P = 0.095) and G:DE intake was greater (P = 0.009) in pigs fed the ALL diet than those fed the NEG diet. Dietary treatments had no clear effect on the growth performance during the phase 2 or overall. Serum total protein and globulin were greater (P < 0.007) in pigs fed the NEG and ALL diets than those fed the POS diets because of the greater values in pigs fed the ALL diets, but those metabolites were not different between pigs fed the NEG and ALL diets. The results indicated that a complex diets can be replaced with a simple corn-SBM diet by supplementing the weanling pig diet with fish peptides and multienzyme complexes during the phase 1 (d 0 to 14).