Retained Energy Research Articles

111 Current and future usage of soybean meal in swine diets in China

Abstract The objective of this presentation was to introduce the utilization tendency and research progress of soybean meal (SBM) in swine diets in China. As for the utilization tendency of SBM in China, it not only brings great pressure to the food security of China, but also directly pushes the high production cost of animal products. In 2022, 117 million tons of protein feed was consumed by the animal husbandry in China, accounting for nearly 1/3 of the total protein feed consumption in the world. Thus, the application of low-protein diet has been promoted with the strong support of the Ministry of Agriculture and Rural Affairs in China since 2018. With the related techniques, including popularizing low protein diet, developing new protein feed resources, promoting precise nutrition, and feeding technology, even though the compound feed output has increased by more than 84 million tons in 2022 in China, the SBM consumption in feed has reduced 6%. Recently, the geopolitical challenges, regional unrest and climate change tendency have increased the great uncertainty of protein feed supply, which requires us to deeply understand the significance of SBM reduction and substitution in animal feed. As for the research progress, the available energy contents of SBM were determined on growing pigs. Barrows [n = 24; initial body weight (BW) = 36 ± 1.4 kg] were randomly allotted to 4 diets containing SBM with either corn basal or corn-soybean meal basal, and total feces and urine collection method and indirect calorimetry method were used to determine the available energy of SBM. The results showed that the average digestible energy (DE), metabolizable energy (ME), net energy (NE), and retained energy (RE) values in SBM [17.36, 16.52, 10.62, and 5.06 MJ/kg dry matter (DM), respectively] determined using the corn-SBM-basal diet were not different from the those determined using the corn-basal diet. Moreover, the best fitted prediction equations developed based on 22 SBM samples produced from soybeans from China (n = 6), USA (n = 6), Brazil (n = 7) or Argentina (n = 3) were: DE = 38.44 - 0.43 CF - 0.98 GE + 0.11 ADF (R2 = 0.67, P < 0.01) and ME = 2.74 + 0.97 DE - 0.06 CP (R2 = 0.79, P < 0.01). The in vitro digestion kinetics of SBM from different sources showed that the release of amino acids in the 0-10 min time interval was significantly negatively correlated with the NE of SBM (R2 = -0.34).

PSIV-A-13 The relationship between breed-wide expected progeny differences, genomic predictors, and phenotypic values in mature Angus cows

Abstract For many years, selection for improved beef production centered on heavier weaning weights and more rapid post-weaning gain. More recently, measurement of post-weaning feed intake has facilitated direct improvement in feed efficiency in the feedlot. However, intake on a high concentrate diet is controlled by different biological mechanisms than intake on a high roughage diet. For this reason, the question remains whether an animal that efficiently converts calories from a high-quality concentrate-based ration similar to that of a feedlot diet where the expected progeny differences (EPDs) and genomic predictors (GPs) are developed would also be an efficient forage utilizer as a mature cow. To evaluate this relationship, we compared breed-wide EPDs and predictors to performance on a roughage diet and on a concentrate diet in mature cows. The objective of this study was to determine if EPDs and GPs developed and used in feedlots are applicable to commercial cow/calf producers utilizing forages and other roughages as the main diet ingredient. Data for this study were collected at Oklahoma State University from the fall of 2018 to the spring of 2021. Tissue samples from 64 mature Angus cows were submitted to Neogen for profiling according to genetic potential for 16 different traits. In each trial, retained energy (RE), dry matter intake (DMI), milk production (MILK), mature weight (MW), and average daily gain (ADG) were recorded and compared with the corresponding EPD and GP. Pearson correlations were determined between phenotypic values, GPs, and EPDs for both diets on each trial. No EPD or GP was significantly correlated to any measured trait on the forage diet. The DMI EPD was strongly correlated with DMI on a concentrate-based diet, however, did not predict DMI on a forage diet in mature cows. Based on the evaluations performed in this study, selecting for animals that perform well in the feedlot may be inadvertently selecting for mature cows that perform poorly on a typical mature cow diet of medium to low-quality forages.

Energy utilization and requirement of broiler breeders during the production phase

This study aimed to evaluate energy utilization and propose models for metabolizable and net energy requirements in broiler breeders during the egg production phase. Sixty Cobb500 broiler breeders aged between 29 and 65 wk were randomly assigned to 3 feeding levels. At each age, 6 birds were adapted for 8 d to 3 levels of metabolizable energy intake (MEi), established based on the amount of feed allocated: 1) the amount of feed recommended in the guideline, 2) 25% above, and 3) 25% below. The birds were housed in respirometry chambers for 6 d (1 adaptation, 4 feeding state, 1 fasting) to measure oxygen consumption and carbon dioxide production to calculate heat production (HP) and fasting HP (FHP). Daily measurements of feed intake, egg weight, egg production, and total excreta were recorded. Variables of MEi, HP, and retained energy (RE) in the egg were calculated, while RE in the body and its partitioning into fat and protein in the egg and body were calculated from MEi, total HP (THP), and RE in the egg. Statistical analysis involved linear regression of multiple factors with MEi and age (categorical) as the independent variables. Pearson correlation analysis was conducted to investigate the relationship between visceral mass and the evaluated variables. The study proposed mixed models for developing models of energy requirements for both metabolizable (ME) and net systems (NE). The study found that FHP (average 259 ± 20.08 kJ/kg0.75*d) remained constant throughout the production cycle regardless of the MEi level (P > 0.05). The efficiency of energy utilization for depositing protein and fat in the body changed with the bird's age. The lower error model was considered to select ME requirements for maintenance, egg, and gain efficiencies, disregarding the effect of age. The efficiencies were 0.89, 0.78, and 0.80 for maintenance, gain, and egg production, respectively. The NE was unaffected by age and showed a lower error than the ME model. The NE system was found to be more accurate in expressing the energy requirements of broiler breeders.

Effects of glucose release kinetics of extruded-maize diet on energy utilization of growing pigs

The precise energy requirement of swine should not only meet the static parameters of net energy but also consider the dynamic supply of glucose release. The effects of glucose release characteristics on nitrogen and energy utilization of growing pigs were conducted by the energy metabolism in vivo using open-circuit respiratory calorimetry and the hydrolysis in vitro of glucose release. Sixteen castrated boars were randomly divided into two groups (Raw maize group and Extruded maize group, RAW and EXT). Maize in the RAW diet was completely replaced by extruded-maize in the EXT diet. In vitro studies showed that extrusion treatment had a rapid and huge glucose release of maize (P < 0.05). The metabolizable energy (ME) in EXT was higher than that in RAW (P = 0.002), but no difference in net energy (NE) was observed (P = 0.864). EXT had higher crude protein (CP) apparent digestibility (P = 0.035) but lower nitrogen deposition (P < 0.001) due to higher urinary nitrogen (UN) excretion (P < 0.001). Extrusion treatment changed the proportion of heat production of carbohydrates, fat, and protein. EXT presented higher oxidation of protein (OXP, P < 0.001) and fat (OXF, P = 0.025) and lower oxidation of carbohydrates (OXCHO, P = 0.003). There was no difference in retained energy (RE) between the two groups (P = 0.803). Extrusion treatment can accelerate the glucose release of maize, and the extruded maize fully replacing raw maize in the diet can enhance ME of growing pigs, and the ratio of nutrient oxidation to energy supply was altered, resulting in lower protein deposition and energy utilization.

Dietary carbohydrates induce a higher SDA than lipids in rainbow trout (Oncorhynchus mykiss) based on environmental temperature.

As global temperatures increase so do the needs to investigate how the energy metabolism of fish responds to a broad range of thermal condition. Limited resources make it additionally important to use them sustainably in the feeds for aquaculture. Here we investigated the use of three different carbohydrate to lipid ratios (1:1; 1: 0.6; 1.4: 1 as non-protein energy substrates (NPES) in diets for rainbow trout (Oncorhynchus mykiss) under five different thermal regimes (12; 14; 16; 18; 20°C) in a bioenergetic approach using a group respirometer. The results showed that the diet with carbohydrate as the main NPES resulted in a quadratic relationship of the specific dynamic action (SDA) values to temperature while diets with lipid as main NPES or a balanced ratio did not show such a response. SDA values in the diet with carbohydrate as the main NPES were significantly higher at temperatures around the optimum (15-17°C) than the diets with lipid as the main NPES or with a balanced carbohydrate to lipid ratio. The retained energy (RE) was highly dependent on the standard metabolic rate (SMR) and SDA values did not carry over onto them. The protein utilization for energy combustion was significantly lower at 12°C in the diet with carbohydrate as the main NPES than in the diet with lipid as the main NPES thus indicating that carbohydrates hold a relevant nutritional value especially at lower temperatures.

98 Utilizing gas Flux from an Automated Head Chamber System to Estimate Dietary Energy Values in Cattle Fed a Finishing Diet

Abstract Automated head chamber systems (AHCS; GreenFeed, C-Lock Inc., Rapid City, SD) provide estimates of daily flux of methane (CH4), carbon dioxide (CO2), and oxygen (O2) from free roaming cattle. This provides the opportunity to conduct energetic research from cattle in their production environment. One opportunity is to evaluate agreement between performance-estimated (P) net energy [Mcal×(kg DMI)-1] for maintenance (NEm) and gain (NEg; pNEm and pNEg, respectively) and gas-estimated (G) NEm and NEg (gNEm and gNEg, respectively). To assess this, yearling steers (n = 54; initial BW = 484.1 ± 26.0 kg) were assigned to one of two pens containing an AHCS and feed bunks designed to measure individual feed intake (Calan Gate; American Calan, Northwood, NH). Steers were transitioned to one of three finishing diets and were then fed for 80 days. Paired day initial and final unshrunk BW were measured on day 0 and 1, and on day 79 and 80, respectively. Following the feeding period, steers were transported to a commercial abattoir where carcass data were collected. Average daily gas flux was utilized to calculate heat production (HP), ignoring the energy losses from urinary nitrogen. Empty body weight (EBW) and empty body gain (EBG) were calculated and used to estimate retained energy (RE). The estimates of RE and HP were used to calculate ME intake and DMI was used to quantify dietary ME content. Through previously established cubic models, gNEm and gNEg were calculated. Ultimately, gNEm and gNEg were estimated from gas flux, DMI, ADG, and initial and final BW. A previously established quadratic model was used to estimate pNEm and pNEg using calculated energy requirements and available carcass parameters. Statistical analyses to compare the P and G energy values were conducted utilizing R (v.4.1.0) to assess precision (Pearson Correlation; r), method agreement (Lin’s Concordance Coefficient Correlation; CCC), Root Mean Square Error of Prediction (RMSEP), and Relative Prediction Error (RPE; RMSEP as a % of average performance estimated values). On average, P provided greater estimates of NEm [0.074 Mcal×(kg DMI)-1] and NEg [0.070 Mcal×(kg DMI)-1] relative to G. The G and P provided values which were highly correlated and had excellent agreement (r = 0.92, P &amp;lt; 0.01; CCC ≥ 0.87) for both NEm and NEg. Additionally, predictive capability was high for NEm (RMSEP = 0.12; RPE = 5.3%) and NEg (RMSEP = 0.11; RPE = 6.8%) between P and G values. The excellent agreement between P and G derived NEm and NEg values suggest that researchers can utilize AHCS to conduct energetic studies with cattle in their production environment. Moreover, the G methodology provides an alternative method for retrospective assessment of animal energetic efficiency.

Effect of live yeast supplementation and feeding frequency in male finishing pigs subjected to heat stress.

In growing pigs, reduced growth during heat stress (HS) is mainly related to decreased feed intake. The study aimed to determine whether the reported positive effects of live yeast (LY) supplementation in HS pigs were due to a modified feeding behaviour or energy metabolism, and if these can be replicated by imposing an increased meal frequency. The effect of LY supplementation [0 (NS) vs. 100 (LY) g/ton of feed], and of feeding window (FW) [unlimited or Unli, 2FW of 1 h each, and 8FW of 15 min each] were measured in entire male finishing pigs (n=36). Ambient temperature was at 22°C during the thermoneutral period (TN; 5 d) and at 28°C during the HS period (5 d). Heat exposure decreased dry matter intake (DMI) and retained energy (RE) (-627 and -460 kJ∙kg BW-0.60∙d-1, respectively; P<0.01). During HS, LY-supplementation in Unli pigs decreased inter-meal intervals (P=0.02) attenuating HS effect on DMI which tended to improve RE (P=0.09). NS-8FW had higher DMI and RE than NS-2FW (P<0.05) but protein deposition (PD) were similar. Supplemented pigs had higher PD during HS regardless of FW (+18 g∙d-1; P=0.03). Comparing the 2FW groups, improved heat tolerance of LY-supplemented pigs were due to improved insulin sensitivity (P<0.05) and latent heat loss capacity after a meal (P<0.05) allowing them to increase their DMI (via an increased number of meals) and thus their energy efficiency. Imposing an increased meal frequency improved DMI in HS pigs but did not replicate positive effects of LY on protein deposition.

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.

PSIV-7 Evaluating Relationships Among Empty Body, Protein, and Fat Gain and Retained Energy for Pre- and Postweaning Calves

Abstract Discrepancies in the predictability of the nutritional equation used to predict empty body gain in preweaning and postweaning calves could be due to differences in proportion of protein and fat in the gain. The objective of this study was to understand the differences in the relationships of empty body weight gain (EBG) with protein (EBP) and fat (EBF) gain, and retained energy (RE) in preweaning and postweaning calves. A literature search was performed to create a dataset comprised of EBG and composition of gain in calves. The relationships of EBG with EBP, EBF, and RE was compared in preweaning and postweaning calves using R statistical software. Pearson correlation coefficients of EBG with EBP, EBF, and RE were 0.971, 0.839, and 0.934 and 0.805, 0.807, and 0.889 for preweaning and postweaning calves, respectively. A nonlinear regression model was used to evaluate the relationship between EBG and RE including the effects of age (defined as 0 for preweaning and 1 for postweaning calves) and type (defined as 0 for dairy and 1 for beef calves), [EBG = (a + b * age + c * type) * RE^ (d + e * age + f * type)]. The power coefficients were not different (P &amp;gt; 0.05) between preweaning and postweaning calves (0.379 and 0.446 ± 0.041, respectively), but the exponents were different (P ≤ 0.05; 0.921 and 0.558 ± 0.079, respectively). In conclusion, the relationship between empty body weight gain and composition of gain differs between preweaning and postweaning calves, suggesting that a more robust equation or group of equations should be used in nutrition models.

Protease supplementation reduced the heat increment of feed and improved energy and nitrogen partitioning in broilers fed maize-based diets with supplemental phytase and xylanase.

An experiment was conducted to explore the effects of digestible amino acid (dAA) concentrations and supplemental protease on live performance and energy partitioning in broilers. Ross 308 male broilers (n = 288) were distributed into 24 floor pens and offered 1 of 4 dietary treatments with 6 replicates from 1 to 35 d of age. Dietary treatments consisted of a 2 × 2 factorial arrangement with dAA concentrations (standard and reduced [34 g/kg below standard]) and supplemental protease (without or with) as the main factors. At 1, 15, 28, and 35 d of age, feed and broilers were weighed to determine live performance. From 20 to 23 d of age, a total of 32 birds (2 birds/chamber, 4 replicates) were placed in closed-calorimeter chambers to determine respiratory exchange (heat production, HP), apparent metabolisable energy (AME), retained energy (RE), and net energy (NE). From 29 to 35 d of age, supplemental protease in the reduced-dAA diet decreased broiler feed conversion ratio (FCR) by 5.6 points, whereas protease supplementation in the standard-dAA diet increased FCR by 5.8 points. The indirect calorimetry assay revealed that supplemental protease decreased (P < 0.05) the heat increment of feed (HIF) by 0.22 MJ/kg. Also, from 20 to 23 d of age, broilers offered the reduced-dAA diet with supplemental protease had a higher daily body weight gain (BWG) (+10.4%), N intake (+7.1%), and N retention (+8.2%) than those offered the standard-dAA with supplemental protease. Broilers offered the reduced-dAA without supplemental protease exhibited a 3.6% higher AME-to-crude protein (CP) ratio than those offered other treatments. Protease supplementation in the standard- and reduced-dAA diets resulted in 2.7% and 5.6% lower AME intake-to-N retention ratios, respectively, compared with the unsupplemented controls. Reduced-dAA increased (P < 0.05) AME intake (+4.8%), RE (+9.8%), NE intake (+5.8%), NE intake-to-CP ratio (+3.0%), and RE fat-to-RE ratio (+8.6%). Protease supplementation increased (P < 0.05) respiratory quotient (+1.2%) and N retention-to-N intake ratio (+2.2%), NE-to-AME ratio (+1.9%), and reduced HP (−3.6%), heat increment (−7.4%), and NE intake-to-N retention (−2.5%). In conclusion, protease positively affected FCR and energy partitioning in broilers; responses were most apparent in diets with reduced-dAA concentrations.

Energy and Protein Requirements for the Maintenance of Growing Male Sika Deer (Cervus nippon).

The objective of this study is to study the effects of dietary intake levels on energy metabolism, carbon (C), and nitrogen (N) balance and to determine the maintenance requirements of energy and protein for male sika deer during their growing period. A total of 16 1-year-old male sika deer with similar body weight (BW) (63.25 ± 2.42 kg) were selected, with four animals per feed intake level. The feeding levels of the four groups for deer were 40, 60, 80, and 100% of the recommended amount, respectively. The nutrient digestibility and methane production were measured through digestion trials and respiratory trials. A 4 × 4 Latin Square design was performed in a respirometry trial. The results show that the apparent digestibility of C and N gradually increased as the level of feed intake decreased. Furthermore, with a decrease in feed intake level, the metabolic energy intake (MEI), heat production (HP), and retained energy (RE) of male sika deer significantly decreased (P < 0.01). The requirements of metabolic energy for maintenance (MEm) and net energy for maintenance (NEm) of growing deer are 251.17 and 223.62 kJ kg−1BW0.75d−1, respectively, as estimated according to the logarithmic regression equations between HP and MEI. The net N requirement for maintenance (NNm) and net protein requirement for maintenance (NPm) of growing male sika deer based on the linear relationship between retained nitrogen (RN) and daily nitrogen intake (NI) were 251.8 mg kg−1BW0.75d−1 and 1.57 g kg−1BW0.75d−1, respectively. The NEm and NPm values obtained from this experiment fill the gap in net energy and protein requirements and serve as basic data for establishing the nutritional standards forsika deer breeding in China.

Determination of energy and protein requirements of preweaned dairy calves: A multistudy approach

The first studies concerning nutrient requirements for preweaned dairy calves were from the 1920s and 1930s; however, few studies were published in the following decades. We aimed to determine energy and protein requirements of preweaning Holstein and Holstein × Gyr dairy calves in a multistudy meta-regression. We used a database composed of individual measurements of 166 preweaned male calves (138 submitted to treatments and 28 used as the reference group) from 4 studies that used the methodology of comparative slaughter. Animals with less than 15/16 of Holstein genetic composition were considered crossbred Holstein × Gyr, whereas other animals were considered Holstein. Net energy requirements for maintenance (NEM) were determined by the regression between heat production and metabolizable energy intake (MEI). The metabolizable energy requirements for maintenance were calculated by the iterative method, and the efficiency of use of metabolizable energy for maintenance was obtained by NEM divided by the metabolizable energy requirements for maintenance. Net energy requirements for gain (NEG) were estimated using a regression of the retained energy (RE) as a function of empty body weight (EBW) and empty body gain (EBG). The efficiency of use of metabolizable energy for gain was estimated by the regression of RE as a function of MEI, but with partitioning the MEI into MEI from liquid feed and MEI from starter feed. Additionally, the effect of a liquid feed (milk or milk replacer) was tested on the slope of the regression. The metabolizable protein requirements for maintenance (MPM) were estimated using the intercept of the regression between the metabolizable protein intake (MPI) and average daily gain. The MPM was determined as the ratio between the intercept and the metabolic body weight. Net protein requirements for gain (NPG) were estimated by the regression between retained protein, EBG, and RE. The efficiency of use of metabolizable protein for gain was estimated by the regression of the retained protein as a function of MPI, but with partitioning the MPI into MPI from liquid feed and MPI from starter feed. Additionally, the effect of a liquid feed (milk or milk replacer) was tested on the regression slope. Breed did not influence any of the nutrient requirements' estimates. The NEM was estimated as 70.2 kcal/metabolic body weight per day. The efficiency of use of metabolizable energy for maintenance observed was 66%. The NEG was estimated by the equation NEG = 0.0901 × EBW0.75 × EBG0.9539. The efficiency of use of metabolizable energy for gain was estimated as 57.6, 49.3, and 41.2% for milk, milk replacer, and starter feed, respectively. The MPM was estimated as 4.22 g/EBW0.75 per day, and the NPG was determined by the equation: NPG = 30.06 × EBG + 70.98 × RE. The efficiency of use of metabolizable protein for gain was estimated as 71.9, 59.2, and 44.4% for milk, milk replacer, and starter feed, respectively. We concluded that no differences were observed in energy and protein requirements between Holstein and Holstein × Gyr crossbred cows. The efficiencies of use of metabolizable energy and protein are greater for milk when compared with milk replacer and starter feed. Therefore, we propose that the equations generated herein should be used to estimate energy and protein requirements of preweaned Holstein and Holstein × Gyr crossbred dairy calves raised under tropical conditions.

Evaluation on Net Energy of Defatted Rice Bran from Different Origins and Processing Technologies Fed to Growing Pigs

Simple SummaryIn recent years, prices of imported staples such as corn and soybean meal have risen dramatically. Defatted rice bran (DFRB), an abundant and underutilized agricultural coproduct of the paddy rice, was a replacement of corn and soybean meal. It is necessary to comprehensively evaluate the nutritional value of DFRB. This study determined and compared the net energy (NE) of DFRB from different sources and different processing technology fed to growing pigs using indirect calorimetry. Results indicated that NE contents of extruded DFRB from different provinces were within the range of values ((8.24 to 10.22 MJ/kg dry matter (DM)). The NE contents of extruded DFRB and pelleted DFRB from the same province were 8.24 vs. 6.56 MJ/kg DM. This study showed that there is a discrepancy of approximately 10.01% in the NE content between the DFRB origins. The data above suggested that NE content of DFRB could be related to DFRB origins and processing technology. More NE contents of different DFRB samples deserve to be explored further. The study supported some theoretical foundation for the application of DFRB in the NE system.The study was conducted to determine and compare the net energy (NE) of defatted rice bran (DFRB) from different sources and different processing technology fed to growing pigs using indirect calorimetry. Thirty-six growing barrows (30.7 ± 3.9 kg) were randomly allotted to 1 of 6 diets with 6 replicate pigs per diet. Diets included a corn-soybean meal basal diet and 5 test diets containing 30% DFRB, respectively. These five samples come from 4 different provinces (i.e., Heilongjiang, Jiangsu, Jilin, and Liaoning province within China) and two of them with the same origin but different processing technologies (i.e., extruded or pelleted). During each period, pigs were kept individually in metabolism crates for 21 days, including 14 days to adapt to the diets. On day 15, pigs were transferred to the open-circuit respiration chambers for adaptation, and the next day were ready to determine daily total heat production (HP) and were fed 1 of the 6 diets at 2.3 MJ metabolizable energy (ME)/kg body weight (BW)0.6/day. Total feces and urine were collected for the determination of digestible energy (DE) and ME and daily total HP was measured from day 16 to day 20 and fasted on day 21 for the measurement of fasting heat production (FHP). The NE contents of extruded DFRB from different provinces were within the range of values (8.24 to 10.22 MJ/kg DM). There is a discrepancy of approximately 10.01% in the NE content between the DFRB origins. The NE contents of extruded DFRB and pelleted DFRB from the same province were 8.24 vs. 6.56 MJ/kg DM. Retained energy (RE) and FHP of diets containing extruded DFRB and pelleted DFRB were 1105 vs. 892 kJ/kg BW0.6/day and 746 vs. 726 kJ/kg BW0.6/day respectively, and those in extruded DFRB from different origins were within the range of values (947 to 1105 kJ/kg BW0.6/day and 726 to 755 kJ/kg BW0.6/day, respectively). In conclusion, NE values are affected by origin and processing technology of DFRB.

Development of equations to predict carcass weight, empty body gain, and retained energy of Zebu beef cattle

The accurate supply of energy is essential to optimize livestock productivity and profitability. Furthermore, replacing empty BW gain (EBG) with carcass gain (CG) might be a suitable alternative to estimate the retained energy (RE) of beef cattle. Thus, this multi-analysis study was conducted aiming to estimate and validate new equations to predict carcass weight (CW), EBG, and RE of Zebu, beef crossbred, and dairy crossbred. A database composed by 1112 animals encompassing bulls, steers, heifers of different genetic groups (Zebu, beef crossbred, and dairy crossbred), and two types of slaughter plants (commercial and experimental) was used for generating the new CW equation. For the development of the EBG and RE equations, a database of 636 observations composed of bulls, steers, and heifers of different genetic groups (Zebu, beef crossbred, and dairy crossbred) was assembled. The validation of new equations was performed using independent databases composed by 137 observations (80 for CW and 57 for EBG and RE). The new approaches for EBG and RE validation also included data from our research group studies (Inside) and independent data from literature publications (Outside). Furthermore, the new RE equation was compared to the current model devised by the nutritional requirements, diet formulation, and performance prediction of Zebu and crossbred cattle (BR-CORTE, 2016). Validation analyses were performed by using the Model Evaluation System (MES; 3.1.13, College Station, US). The CW was accurately estimated by the new equation when using both commercial and experimental data. Also, the equations developed in this study accurately estimated EBG and RE using both inside and outside data. In conclusion, equations proposed in this study accurately and precisely estimated CW, EBG, and RE of Zebu beef cattle that composed validation data set. Therefore, we suggest the following equations to estimate CW, EBG, and RE of Zebu cattle: CW, kg = −11.0±1.56 + P + ((0.609±0.005 + G + B) × SBW); EBG (kg) = 0.044±0.017 + 1.47±0.026 × CG; RE (MJ/d) = 4.184 × (0.082±0.002 × EQEBW0.75 × CG0.777±0.039), where P = slaughter plant effect, if commercial = −10.98, if experimental =0; G = gender effect, if steer = 0, if bull = 0.008169 and if heifer = −0.00612; B = genotype effect, if Zebu = 0, if dairy crossbreds = −0.03301 and if beef crossbreds = −0.01595; SBW = shrunk BW; CG = carcass gain; EQEBW = equivalent empty BW.

351 Awardee Talk: How retained energy and protein affects the determination of energy and protein requirements for growth

Abstract The understanding of how nutrition influences the body composition of growing animals has fascinated researchers for centuries. It involves the expertise of scientists with different areas of knowledge, encompassing the composition of the diet and its nutritive value to the fermentation and digestion of substrates to the absorption and metabolism of nutrients, and finally, to the deposition of fat, protein, and minerals in body tissues. The comparative slaughter technique is the preferred method to assess the body composition of growing and finishing animals. However, the methodological procedures are labor-intensive, expensive, and time-consuming, facilitating the incidence of errors and inconsistencies of the measurements that are collected, including the initial animal’s body composition. First, retained fat and protein (RP) are used to compute retained energy (RE). Then, RP and RE are used to compute protein and energy requirements for growth. Heat production, calculated from the metabolizable energy (ME) intake for animals at maintenance, is used to compute maintenance requirements. Three areas of concern exist for this approach: 1) the efficiencies of possible mobilization of fat and protein tissues during the feeding period are unaccounted for, especially for the animals fed near the maintenance level of intake; 2) the correlation between observed and predicted RP when using predicted RE is higher than when using observed RE (0.939 vs. 0.679); and 3) the disconnection when predicting partial efficiency of use of ME for growth using the proportion of RE deposited as protein — carcass approach — versus using the concentration of ME of the diet — diet approach. These concerns raised questions about the interdependency between predicted RP and RE and the existence of internal offsetting errors that may prevent overall adequacy in predicting energy and protein requirements of beef cattle.

Multi-carbohydrase effects on energy utilization depend on soluble non-starch polysaccharides-to-total non-starch polysaccharides in broiler diets

Non-starch polysaccharides (NSP), especially in water-soluble form, are a common anti-nutritional factor in cereal-based poultry diets. Consequently, carbohydrases are applied to diets to combat the negative effects of NSP on bird performance and health, particularly when feeding viscous grains. This study investigated the effect of supplementing multi-carbohydrases (MC) to broiler diets containing either low (LS) or high (HS) soluble NSP (sNSP) to total NSP (tNSP) ratios on energy partitioning, nitrogen (N) balance, and performance. A 2 × 2 factorial arrangement of treatments (MC, no or yes; sNSP/tNSP, LS vs. HS) was applied, resulting in 4 dietary treatments, each replicated 8 times. These treatments were fed to Ross 308 broilers in closed-circuit indirect calorimetry chambers, with 2 birds (a male and a female) per replicate chamber (n = 64). The results showed that MC addition increased AME, net energy (NE), and AME/gross energy, regardless of sNSP/tNSP content (P < 0.01 for all). There was an MC × sNSP/tNSP interaction for feed intake (FI, P < 0.05), denoting that in the absence of MC, the HS-fed birds had lower FI than LS-fed birds, but this difference was eliminated when MC was present. There were MC × sNSP/tNSP interactions observed for AME intake (AMEi) per metabolic BW (BW0.70, P < 0.05), AMEi/N retention (Nr, P < 0.01), NE intake (NEi)/Nr (P < 0.05), retained energy (RE) as fat per total RE (REf/RE, P < 0.01), and N efficiency (Nr/N intake, P < 0.05). These interactions showed that MC application increased AMEi/BW0.70, AMEi/Nr, NEi/Nr, and REf/RE only in the HS-fed birds, and N efficiency only in the LS-fed broilers. This study demonstrated that MC application markedly increased feed energy utilization in all diets, and increased N efficiency in birds fed an LS diet.

Implementation of net energy evaluating system in laying hens: Validation by performance and egg quality

Three experiments were conducted to determine the effect of different dietary net energy (NE) and AMEn ratios (NE:AMEn) on performance, egg quality, and heat production (HP) in laying hens. In experiment 1, 62 Hy-Line Brown hens were fed 2 treatments with 31 replicates from 44 to 54 wk of age. In experiment 2, 600 hens of the same strain were fed 3 treatments from 22 to 42 wk of age with 10 replicates. Both used a completely randomized design. Diets were based on corn, wheat, wheat bran, barley, soybean meal, canola meal, meat and bone meal, and canola oil. In both experiments, the NE:AMEn ratio of diets was increased with higher oil inclusion compared with T1 controls. The AMEn (kcal/kg), NE (kcal/kg), ether extract (g/kg), and CP (g/kg), respectively, on a DM basis in experiment 1 was T1: 3,011, 2,288, 42, 202 and T2: 3,023, 2,374, 81, 203; and in experiment 2, T1: 3,026, 2,324, 25, 187; T2: 2,949, 2,315, 61, 185; and T3: 3,026, 2,397, 73, 181. Increasing the ratio of NE:AMEn decreased feed intake (P < 0.001) and increased egg mass (P < 0.05) in experiment 2 and increased egg weight (P < 0.01), decreased feed conversion ratio (P < 0.01), increased egg albumen % (P < 0.001), and decreased yolk % (P < 0.05) and shell % (P < 0.05) compared with T1 controls in both experiments. Haugh units and yolk color scores were increased with high NE:AMEn in both experiments (P < 0.001; P < 0.01). Experiment 3 was conducted in calorimetry chambers to measure HP in birds fed experiment 2 diets. Increasing the NE:AMEn increased total retained energy (RE), RE as fat, and RE in the body (kcal/kg BW0.75/D) and NE:AME. The results indicate that using oil to increase the NE:AMEn results in improved performance and egg quality and more efficient energy utilization.

Metabolisable energy partition for Japanese quails

Knowing how energy intake is partitioned between maintenance, growth and egg production (EP) of birds makes it possible to structure models and recommend energy intakes based on differences in the BW, weight gain (WG) and EP on commercial quail farms. This research was a dose-response study to re-evaluate the energy partition for Japanese quails in the EP phase, based on the dilution technique to modify the retained energy (RE) of the birds. A total of 300 VICAMI® Japanese quail, housed in climatic chambers, were used from 16 weeks of age, with averages for BW of 185 g and EP of 78%, for 10 weeks. To modify the RE in the bird’s body, a qualitative dilution of dietary energy was used. Ten treatments (metabolisable energy levels) were distributed in completely randomised units, with six replicates of five quails per experimental unit. Metabolisable energy intake (MEI), egg mass (EM) and RE were expressed in kJ/kg0.67. The utilisation efficiency (kt) was estimated from the relationship between RE and MEI. The metabolisable energy for maintenance was given by RE = 0. The net energy requirement for WG was obtained from the relationship between RE in the BW as a function of the BW. The utilisation efficiency for EP (ko) was obtained from the relationship between EM and RE corrected MEI for maintenance and WG. Based on these efficiencies, the requirements for WG and EM were calculated. The energy intake by Japanese quails was partitioned according to the model: MEI = 569.8 × BW0.67 + 22 × WG + 13 × EM. The current study provides procedures and methods designed for quails as well as a simple and flexible model that can be quickly adopted by technicians and poultry companies.

Net Energy Net Energy Net EnergyNet EnerNet Energy of high-protein sunflower meal fed to growing pigs and effect of dietary phosphorus on measured values of NE.

An experiment was carried out to determine energy values of high-protein sunflower meal (HP-SFM) and to compare the energy values of HP-SFM determined using either a phosphorus (P)-deficient basal diet or a P-adequate basal diet. Twenty-four growing barrows were randomly assigned to 1 of 4 dietary treatments with 6 replicates per treatment. Four experimental diets including 2 basal diets containing 2 levels of standardized total tract digestible P (i.e., P-deficient and P-adequate) and the other 2 diets containing 30% HP-SFM with each basal diet (i.e., HP-SFM 1 diet and HP-SFM 2 diet) were formulated to determine the energy values of HP-SFM and to compare energy values of HP-SFM determined by the difference method using 2 basal diets. Pigs were fed diets for 15 d including 10 d for adaptation and 5 d for total collections. Pigs were then moved to indirect calorimetry chambers to determine total heat production (THP) and fasting heat production (FHP). A reduced (P < 0.01) amount of nitrogen was retained in pigs fed the P-deficient basal diet compared with those fed the other diets. The THP of pigs fed the HP-SFM 1 and 2 diets was greater (P < 0.01) than those fed the P-deficient basal diet with the intermediate value for pigs fed the P-adequate basal diet. The retained energy (RE) as protein of pigs fed the P-deficient basal diet was less (P < 0.01) but RE as lipid was greater (P < 0.01) than those fed the P-adequate basal, or HP-SFM 1 and 2 diets. However, there was no difference in FHP of pigs among the dietary treatments. The NE of HP-SFM determined using the P-deficient basal diet was 2,062 kcal/kg, as-fed basis, whereas the value determined using the P-adequate basal diet was 2,151 kcal/kg. Although no differences were observed in energy values, the amount of P in basal diet might affect energy balance by modifying N utilization, thus, a diet containing adequate amount of P is a more suitable basal diet when the difference method is used for calculation of NE in a feed ingredient.

Estimation of the net energy and protein requirements for maintenance of male arctic foxes (Alopex lagopus) during the growth period1,2.

The maintenance requirements of net energy and net protein were assumed to represent the most accurate and important values totally for the animal's utilization. The objective of this experiment was to determine the net energy and net protein requirements for maintenance of growing arctic foxes. The experiments was evaluated using regression models estimated from data collected by means of indirect calorimetry, nitrogen balance trials, and digestion and metabolism experiments. Thirty-six growing arctic foxes (3 487 ± 261.7 g) at the age of 85 days were randomly assigned to four groups with 9 animals in each group. Arctic foxes were fed a complete formula diet at four intake levels (100%, or 80%, 60%, and 40% of feed requirements) from 24 July 2017 to 23 September 2017. Arctic foxes in each treatment were kept individually in respiration chambers after 1-d adaptation at day 2 for a 3-d balance trial and then at day 5 followed by a 3-d fasting period. The metabolizable energy intake (MEI), heat production in the fed state (HP), and retained energy (RE) of arctic foxes significantly decreased (P < 0.01) as the feed intake level decreased. Fasting heat production (FHP) of arctic foxes was not influenced by feed intake level (P > 0.05). The metabolizable energy maintenance requirement (MEm) and net energy maintenance requirement (NEm) estimated from the linear relationship between RE and MEI were 230 and 217 kJ/kg of body weight BW0.75/d, respectively. The MEm and NEm estimated by logarithmic regression of HP on MEI were 225 and 209 kJ/kg BW0.75/d, respectively. The net N maintenance requirement (NNm) and net protein maintenance requirement (NPm) estimated from the linear relationship between retained nitrogen (RN) and daily nitrogen intake (NI) were 179.6 mg/kg BW0.75/d and 1.123 g/kg BW0.75/d, respectively. It is concluded that NEm and NPm values obtained fill the net energy and protein requirements shortage, and provide the basic data for establishing the standard of nutrition demand of breeding arctic foxes in China.