Maintenance Energy Requirements Research Articles

Bedding Application to Feedlot Steers: Influence on Growth Performance, Estimated Maintenance Coefficient, Carcass Characteristics, and Circulating Metabolites in Beef Steers.

Simple SummaryA sizeable portion of cattle fed in the United States are fed in the Upper Midwest and Northern Plains where winter temperatures routinely fall below freezing. Using bedding application to improve cattle comfort and performance has been a common practice in livestock production for many years. However, the exact degree to which bedding improves performance is difficult to quantify. As such, two studies were conducted to evaluate the effects of bedding use on growth performance, estimated maintenance energy requirement, carcass characteristics, sera responses in beef steers of differing ages, and phases of feedlot production. Experiment 1 showed that applying wheat straw bedding to yearling crossbred beef steers at a rate of 1.8 kg/steer·d−1 increased feed consumption, feed efficiency, and average daily gain. In experiment 2, newly weaned calves bedded with 1.0 kg of wheat straw bedding/steer·d−1 tended to consume 4.5% less feed and had a 5.6% improvement in feed efficiency. In both studies, the energy required for maintenance for non-bedded steers was increased. These experiments indicate that bedding application should be considered to improve growth performance and feed efficiency in beef steers by reducing maintenance energy requirements during the feedlot receiving and finishing phases.Two randomized complete block design experiments were conducted to evaluate the effect of bedding use in confined beef steers. Experiment 1 used Simmental × Angus steers (n = 240; initial body weight (BW) = 365 ± 22.5 kg). Experiment 2 used newly weaned Charolais × Red Angus steers (n = 162; initial BW = 278 ± 13.4 kg). Steers were allotted to one of two treatments: (1) no bedding (NO), or (2) 1.8 kg (Experiment 1) or 1.0 kg (Experiment 2) of wheat straw (as-is basis) bedding/steer·d−1 (BED). In Experiment 1, applying bedding improved (p ≤ 0.01) dry matter intake (DMI), kg of gain to kg of feed (G:F), and average daily gain (ADG). Bedding reduced (p = 0.01) the estimated maintenance coefficient (MQ). Dressing percentage, rib fat, marbling, and yield grade were increased (p ≤ 0.03) in NO. Bedding resulted in an increase (p = 0.01) in serum insulin-like growth factor I (IGF-I). In Experiment 2, a tendency (p = 0.06) for increased DMI for NO was noted. Bedding improved G:F (p = 0.01). MQ was elevated (p = 0.03) for NO and NO had an increase (p = 0.02) in serum concentration of urea-N (SUN). An increase (p = 0.01) in serum non-esterified fatty acid was noted for NO. These data indicate that bedding application should be considered to improve growth performance and feed efficiency by reducing maintenance energy requirements in beef steers during the feedlot receiving and finishing phase.

Effects of High-Fat Diet at Two Energetic Levels on Fecal Microbiota, Colonic Barrier, and Metabolic Parameters in Dogs.

Increased consumption of energy-rich foods is a key factor in overweight, obesity, and associated metabolic disorders. This would be, at least in part, related to microbiota disturbance. In rodent models of obesity, microbiota disruption has been associated with alteration of the intestinal barrier, endotoxemia, inflammation grade, and insulin sensitivity. The aim of the present study was to assess the effects of a high-fat diet (HFD), fed at two energetic levels, on microbiota, intestinal barrier, and inflammatory and metabolic parameters in dogs. A HFD (33% fat as fed, 4,830 kcal/kg) was given to 24 healthy Beagle dogs at 100% (HF-100; n = 8) and at 150% (HF-150; n = 16) of their maintenance energy requirements for 8 weeks. Analysis of similarity revealed a significant difference in gut microbiota β-diversity following the diet compared to week 0 in both groups while α-diversity was lower only in the HF-150 group. Firmicutes/Bacteroidetes ratio was higher in the HF-150 group compared to the HF-100 group at weeks 2 and 8. A reduction in insulin sensitivity was observed over time in the HF150 group. Neither endotoxemia nor inflammation was observed in either group, did not find supporting data for the hypothesis that the microbiota is involved in the decline of insulin sensitivity through metabolic endotoxemia and low-grade inflammation. Colonic permeability was increased at week 4 in both groups and returned to initial levels at week 8, and was associated with modifications to the expression of genes involved in colonic barrier function. The increase in intestinal permeability may have been caused by the altered intestinal microbiota and increased expression of genes encoding tight junction proteins might indicate a compensatory mechanism to restore normal permeability. Although simultaneous changes to the microbiota, barrier permeability, inflammatory, and metabolic status have not been observed, such a causal link cannot be excluded in dogs overfed on a HFD. Further studies are necessary to better understand the link between HFD, intestinal microbiota and the host.

1200 high-quality metagenome-assembled genomes from the rumen of African cattle and their relevance in the context of sub-optimal feeding

BackgroundThe Boran (Bos indicus), indigenous Zebu cattle breed from sub-Saharan Africa, is remarkably well adapted to harsh tropical environments. Due to financial constraints and low-quality forage, African livestock are rarely fed at 100% maintenance energy requirements (MER) and the effect of sub-optimal restricted feeding on the rumen microbiome of African Zebu cattle remains largely unexplored. We collected 24 rumen fluid samples from six Boran cattle fed at sub-optimal and optimal MER levels and characterised their rumen microbial composition by performing shotgun metagenomics and de novo assembly of metagenome-assembled genomes (MAGs). These MAGs were used as reference database to investigate the effect of diet restriction on the composition and functional potential of the rumen microbiome of African cattle.ResultsWe report 1200 newly discovered MAGs from the rumen of Boran cattle. A total of 850 were dereplicated, and their uniqueness confirmed with pairwise comparisons (based on Mash distances) between African MAGs and other publicly available genomes from the rumen. A genome-centric investigation into sub-optimal diets highlighted a statistically significant effect on rumen microbial abundance profiles and a previously unobserved relationship between whole microbiome shifts in functional potential and taxon-level associations in metabolic pathways.ConclusionsThis study is the first to identify 1200 high-quality African rumen-specific MAGs and provides further insight into the rumen function in harsh environments with food scarcity. The genomic information from the rumen microbiome of an indigenous African cattle breed sheds light on the microbiome contribution to rumen functionality and constitutes a vital resource in addressing food security in developing countries.

Feeding behavior, water intake, and energy and protein requirements of young Nellore bulls with different residual feed intakes.

This study aimed to determine feeding behavior, water intake (WI), and energy requirements of high- and low-residual feed intake (RFI) Nellore bulls. Data were collected from 42 weaned Nellore bulls (initial body weight [BW] 260 ± 8.1 kg; age 7 ± 1.0 mo) housed in a feedlot in group pens that contained electronic feeders, waterers, and a scale connected to the waterers. The individual dry matter intake (DMI), WI, and BW were recorded daily. The indexes of average daily gain (ADG), feed efficiency (gain to feed ratio), and RFI were calculated based on the data collected. The number of feeder and waterer visits and the time spent feeding or drinking water per animal per day were recorded as feeding behavior measures. Energy requirements for maintenance and gain were calculated according to the BR-CORTE system. Low-RFI bulls had lower DMI (P < 0.01) than high-RFI bulls, and no differences (P > 0.05) were observed between the two groups regarding WI, performance, and feeding behavior measurements. The net energy requirements for maintenance, metabolizable energy for maintenance, and efficiency of metabolizable energy utilization were 63.4, 98.6 kcal/metabolic empty body weight (EBW)0.75 daily, and 64.3%, respectively, for low-RFI bulls, and 78.1, 123.9 kcal/EBW0.75 daily, and 63.0%, respectively, for high-RFI bulls. The equations obtained for net energy for gain (NEg) were: NEg (Mcal/EBW0.75) daily = 0.0528 × EBW0.75 × EBG0.5459 for low-RFI and 0.054 × EBW0.75 × EBG0.8618 for high-RFI bulls, where EBG is the empty body gain. We did not observe any difference (P > 0.05) regarding the composition of gain in terms of protein or fat deposition between the two groups. Both groups also presented similar (P > 0.05) carcass and non-carcass traits. Therefore, our study shows that low-RFI Nellore bulls eat less, grow at a similar rate, and have lower maintenance energy requirements than high-RFI bulls. We also suggest that the lower feed intake did not compromise the carcass traits of more efficient animals, which would reduce production costs and increase the competitiveness of the Brazilian beef sector on the world market.

A survey and critical review of wombat diets in captivity

Much of the literature on wombat diet is concerned only with the broad categories of consumed matter, and there is little about their specific nutritional requirements despite diet playing a major role in health. This study gathered information by surveying zoological parks and wildlife carers about current feeding regime, diet and the prevalence of nutritional or dental disorders of wombats held in captivity, with the aim of improving the diets of captive wombats, thus their health and welfare outcomes. Data on the composition, variation and basis of diets for 31 bare-nosed or common wombats (Vombatus ursinus) and 19 southern hairy-nosed wombats (Lasiorhinus latifrons) were gathered from 13 facilities. The nutritional values of diets fed to wombats in captivity were calculated and compared with known dietary requirements for bare-nosed wombats. Results demonstrate that the current diet of wombats held in captivity often consists of a high portion of fruits, vegetables and livestock feed, with the fruit and vegetable portions providing higher levels of simple carbohydrates and starch compared with natural grass diets. Generally, the facilities are providing diets that are exceeding reported maintenance energy and nitrogen requirements. Due to a lack of details provided regarding quantity and species of grasses fed, we could not provide an accurate ration calculation for the proportion of grasses in the diets. Some of the health concerns noted included insufficient weight gain, endoparasites, malocclusion and insufficient tooth wear. Further research is required to assess the requirements of reproductive, lactating and juvenile wombats; however, it is clear that wombats in captivity need to be fed larger volumes and varieties of grasses, forbs and sedges than they are currently being fed to maintain good health.

Energy Requirement Is Higher During Weight-Loss Maintenance in Adults Consuming a Low- Compared with High-Carbohydrate Diet

ABSTRACTBackgroundLonger-term feeding studies suggest that a low-carbohydrate diet increases energy expenditure, consistent with the carbohydrate-insulin model of obesity. However, the validity of methodology utilized in these studies, involving doubly labeled water (DLW), has been questioned.ObjectiveThe aim of this study was to determine whether dietary energy requirement for weight-loss maintenance is higher on a low- compared with high-carbohydrate diet.MethodsThe study reports secondary outcomes from a feeding study in which the primary outcome was total energy expenditure (TEE). After attaining a mean Run-in weight loss of 10.5%, 164 adults (BMI ≥25 kg/m2; 70.1% women) were randomly assigned to Low-Carbohydrate (percentage of total energy from carbohydrate, fat, protein: 20/60/20), Moderate-Carbohydrate (40/40/20), or High-Carbohydrate (60/20/20) Test diets for 20 wk. Calorie content was adjusted to maintain individual body weight within ± 2 kg of the postweight-loss value. In analyses by intention-to-treat (ITT, completers, n = 148) and per protocol (PP, completers also achieving weight-loss maintenance, n = 110), we compared the estimated energy requirement (EER) from 10 to 20 wk of the Test diets using ANCOVA.ResultsMean EER was higher in the Low- versus High-Carbohydrate group in models of varying covariate structure involving ITT [ranging from 181 (95% CI: 8–353) to 246 (64–427) kcal/d; P ≤0.04] and PP [ranging from 245 (43–446) to 323 (122–525) kcal/d; P ≤0.02]. This difference remained significant in sensitivity analyses accounting for change in adiposity and possible nonadherence.ConclusionsEnergy requirement was higher on a low- versus high-carbohydrate diet during weight-loss maintenance in adults, commensurate with TEE. These data are consistent with the carbohydrate-insulin model and lend qualified support for the validity of the DLW method with diets varying in macronutrient composition. This trial was registered at clinicaltrials.gov as NCT02068885.

Homemade versus extruded and wet commercial diets for dogs: Cost comparison.

The present study aimed to verify and compare the costs of homemade diets with extruded and wet commercial diets for dogs in maintenance and consuming therapeutic diets (obesity, congestive heart failure, diabetes, hepatic encephalopathy, chronic kidney disease, and food hypersensitivity), which is important information that impacts in the choice of food by the owners. The maintenance energy requirements (MER) were estimated for adult dogs of different sizes (3 kg, 15 kg, 30 kg, and 50 kg) and the daily amounts of food intake were estimated for each type of food. The costs were calculated per day, per 1000 kcal of metabolizable energy of product and per kg of metabolic weight of the animal. Fourteen complete and balanced homemade diets were formulated, and in each proposed group, two diets with different protein sources were used. Under the conditions of the present study, it was possible to conclude that homemade diets were more expensive than dry maintenance diets and dry therapeutic diets, while commercial wet diets were more expensive in all of the scenarios.

Metabolic uncoupler, 3,3′,4′,5-tetrachlorosalicylanilide addition for sludge reduction and fouling control in a gravity-driven membrane bioreactor

The gravity-driven membrane bioreactor (MBR) system is promising for decentralized sewage treatment because of its low energy consumption and maintenance requirements. However, the growing sludge not only increases membrane fouling, but also augments operational complexities (sludge discharge). We added the metabolic uncoupler 3,3′,4′,5-tetrachlorosalicylanilide (TCS) to the system to deal with the mentioned issues. Based on the results, TCS addition effectively decreased sludge ATP and sludge yield (reduced by 50%). Extracellular polymeric substances (EPS; proteins and polysaccharides) decreased with the addition of TCS and were transformed into dissolved soluble microbial products (SMPs) in the bulk solution, leading to the break of sludge flocs into small fragments. Permeability was increased by more than two times, reaching 60–70 L/m2/h bar when 10–30 mg/L TCS were added, because of the reduced suspended sludge and the formation of a thin cake layer with low EPS levels. Resistance analyses confirmed that appropriate dosages of TCS primarily decreased the cake layer and hydraulically reversible resistances. Permeability decreased at high dosage (50 mg/L) due to the release of excess sludge fragments and SMP into the supernatant, with a thin but more compact fouling layer with low bioactivity developing on the membrane surface, causing higher cake layer and pore blocking resistances. Our study provides a fundamental understanding of how a metabolic uncoupler affects the sludge and bio-fouling layers at different dosages, with practical relevance for in situ sludge reduction and membrane fouling alleviation in MBR systems.

Contribution of Complex I NADH Dehydrogenase to Respiratory Energy Coupling in Glucose-Grown Cultures of Ogataea parapolymorpha

The thermotolerant yeast Ogataea parapolymorpha (formerly Hansenula polymorpha) is an industrially relevant production host that exhibits a fully respiratory sugar metabolism in aerobic batch cultures. NADH-derived electrons can enter its mitochondrial respiratory chain either via a proton-translocating complex I NADH-dehydrogenase or via three putative alternative NADH dehydrogenases. This respiratory entry point affects the amount of ATP produced per NADH/O2 consumed and therefore impacts the maximum yield of biomass and/or cellular products from a given amount of substrate. To investigate the physiological importance of complex I, a wild-type O. parapolymorpha strain and a congenic complex I-deficient mutant were grown on glucose in aerobic batch, chemostat, and retentostat cultures in bioreactors. In batch cultures, the two strains exhibited a fully respiratory metabolism and showed the same growth rates and biomass yields, indicating that, under these conditions, the contribution of NADH oxidation via complex I was negligible. Both strains also exhibited a respiratory metabolism in glucose-limited chemostat cultures, but the complex I-deficient mutant showed considerably reduced biomass yields on substrate and oxygen, consistent with a lower efficiency of respiratory energy coupling. In glucose-limited retentostat cultures at specific growth rates down to ∼0.001 h-1, both O. parapolymorpha strains showed high viability. Maintenance energy requirements at these extremely low growth rates were approximately 3-fold lower than estimated from faster-growing chemostat cultures, indicating a stringent-response-like behavior. Quantitative transcriptome and proteome analyses indicated condition-dependent expression patterns of complex I subunits and of alternative NADH dehydrogenases that were consistent with physiological observations.IMPORTANCE Since popular microbial cell factories have typically not been selected for efficient respiratory energy coupling, their ATP yields from sugar catabolism are often suboptimal. In aerobic industrial processes, suboptimal energy coupling results in reduced product yields on sugar, increased process costs for oxygen transfer, and volumetric productivity limitations due to limitations in gas transfer and cooling. This study provides insights into the contribution of mechanisms of respiratory energy coupling in the yeast cell factory Ogataea parapolymorpha under different growth conditions and provides a basis for rational improvement of energy coupling in yeast cell factories. Analysis of energy metabolism of O. parapolymorpha at extremely low specific growth rates indicated that this yeast reduces its energy requirements for cellular maintenance under extreme energy limitation. Exploration of the mechanisms for this increased energetic efficiency may contribute to an optimization of the performance of industrial processes with slow-growing eukaryotic cell factories.

Effect of endogenous metabolisms on survival and activities of denitrifying phosphorus removal sludge under various starvation conditions

Denitrifying phosphorus removal sludge are usually faced with various famine environments in wastewater treatment plants (WWTPs). Endogenous metabolisms under aerobic, anoxic, and anaerobic starved conditions were characterized to investigate their impact on survival and activities of denitrifying polyphosphate accumulating organisms (DPAOs). DPAOs utilized intracellular polymers to survive and presented diverse consumed priorities of PHA types under various starvations. The biomass decay rate was approximately 2.7 and 1.7 times lower for aerobic condition than for anoxic and anaerobic conditions owing to the maximum maintenance energy requirement for aerobic condition (68.6 mmol/C-molVSS ATP). During short-term starvations, significant activity decay for anaerobic starved sludge was attributed to its distinctive endogenous metabolisms. For long-term starvations, the higher amounts and preponderant type of PHA (PHB) reserve favored to the greater DPAO activities for anoxic starved sludge. The results show that anoxic condition may be an implementable strategy for maintaining denitrifying phosphorus removal performance in WWTPs.

Energy partitioning and energy efficiency of two Holstein genotypes under a mixed pasture-based system during mid and late lactation

The objective was to evaluate the effect of the Holstein genotype (North American Holstein vs. New Zealand Holstein; NAHvs.NZH, respectively) in a pasture-based system on heat production (HP), energy partitioning between maintenance and production (milk and tissue) and energy efficiency during two different stages of lactation. Twenty-eight Holstein dairy cows (14 cows of each genotype) with similar calving date (May 5, 2018 ± 23 days) were managed in a pasture-based system and supplemented with one third of the predicted total dry matter intake as concentrate. Heat production, retained energy in milk and tissue, metabolizable energy intake (MEI) and the proportion of MEI retained in milk + tissue (RE/MEI) were measured at 115 and 192 ± 19 days in milk and residual HP was estimated by the difference between measured HP and predicted HP based on NRC (2001) model according to body weight, body condition score and milk production. The NAH cows were 60 ± 15 kg heavier and produced 4.7 ± 1.0 kg/d more milk with lower percentages of fat and protein than NZH cows. However, there were no differences in fat or protein yield per day between genotypes. Metabolizable energy intake, retained energy in milk and tissue, HP and RE/MEI were not different between genotypes at 115 days in milk. Nevertheless, at 192 days in milk the MEI, HP and residual HP were lower in NZH than NAH, whereas RE/MEI was not different when both genotypes were managed under a pasture-based system with one third of the consumed diet as concentrate. The capacity of NZH cows to maintain the same RE/MEI than NAH cows at 192 days in milk despite of the lower MEI, was due to a lower metabolizable energy requirement for maintenance (853 vs. 729 kJ/body weight0.75 per day for NAH and NZH, respectively). Indeed, the lower energy requirement for maintenance in NZH was associated with a lower fasting heat production since kl were not different between genotypes. Thus, NZH cows could have a lower proportion of their body as protein mass or a lower relative mass of the internal organs involved with digestive and circulatory functions. However, further investigation is necessary to understand the differences in maintenance energy requirements between the Holstein genotypes.

Energy requirements for pregnant dairy cows.

This study aimed to estimate energy requirements of pregnant Holstein × Gyr cows. Different planes of nutrition were established by two feeding regimens: ad libitum or maintenance. Sixty-two nonlactating cows with average body weight of 480 ± 10.1 kg and an age of 5 ± 0.5 years were used. Cows were divided into three groups: pregnant (n = 44), non-pregnant (n = 12), and baseline reference (n = 6). The 56 pregnant and non-pregnant cows were randomly allocated into a feeding regimen: ad libitum or maintenance. To evaluate the effects of days of pregnancy, pregnant and non-pregnant animals were slaughtered at 140, 200, 240, and 270 days of pregnancy. Energy requirements for maintenance differed between pregnant and non-pregnant cows, thus two equations were developed. Net energy and metabolizable energy requirements for maintenance of non-pregnant cows were 82 kcal/kg empty body weight0.75/day and 132 kcal/kg empty body weight0.75/day, respectively. The efficiency of use of metabolizable energy for maintenance of non-pregnant cows was 62.4%. Net energy and metabolizable energy for maintenance of pregnant cows were 86 kcal/kg empty body weight0.75/day and 137 kcal/kg empty body weight0.75/day, respectively. Efficiency of use of metabolizable energy for maintenance of pregnant cows was 62.5%. The efficiency of use of metabolizable energy for gain was 41.9%. The efficiency of use of metabolizable energy for pregnancy was 14.1%. Furthermore, net energy requirement for pregnancy was different from zero from day 70 of pregnancy onwards. In conclusion, net energy and metabolizable energy requirements for maintenance of non-pregnant cows are different from pregnant cows. Furthermore, we believe that the proposed non-linear equations to estimate net energy requirements for pregnancy are more adequate than current NRC equation, and should be recommended for Holstein × Gyr cows.

Metabolomics of Milk Reflects a Negative Energy Balance in Cows.

Dairy cows can experience a negative energy balance (NEB) in early lactation when feed intake is too low to meet the energy requirements for body maintenance and milk production. Metabolic changes occur in mammary gland cells of animals experiencing a negative energy balance. We studied these metabolic changes in milk samples from dairy cows in relation to energy balance status using liquid chromatography–mass spectrometry (QQQ-LC–MS) and nuclear magnetic resonance (1H NMR). NMR and LC–MS techniques are complementary techniques that enabled a comprehensive overview of milk metabolites in our study. Energy balance and milk samples were obtained from 87 dairy cows. A total of 55 milk metabolites were reliably detected, of which 15 metabolites were positively correlated to energy balance and 20 were negatively correlated to energy balance. Cows in NEB produced more milk with increased milk fat yield and higher concentrations of citrate, cis-aconitate, creatinine, glycine, phosphocreatine, galactose-1-phosphate, glucose-1-phosphate, UDP-N-acetyl-galactosamine, UDP-N-acetyl-glucosamine, and phosphocholine but lower concentrations of choline, ethanolamine, fucose, N-acetyl-neuraminic acid, N-acetyl-glucosamine, and N-acetyl-galactosamine. During NEB, we observed an increased leakage of cellular content, increased synthesis of nucleic acids and cell membrane phospholipids, an increase in one-carbon metabolic processes, and an increase in lipid-triglyceride anabolism. Overall, both apoptosis combined with cellular renewal is paramount in the mammary gland in cows in NEB.

Energy input-output analysis of rice production in Nigeria

Abstract Energy input-output assessment for crop production processes is becoming increasingly important due to increased energy demand. Efficient use of energy can help achieve an environmentally, economically and socially viable sustainable crop production system now and for the future in general. This paper explores the energy inputs and consumption patterns for rice production system in Nigeria. Energy related data were collected through field surveys, direct measurements, interview with farmers and structured questionnaires for two growing seasons in nine (9) rice farms, comprising of three small, medium and large farms, respectively. Energy requirement for land preparation, planting, crop maintenance (fertilization and weed control), threshing, and harvesting were calculated using standard equations. The average energy input for rice production in small, medium and large farms were 14813, 14543 and 14067 MJ/ha, respectively, while the average yield obtainable were 6695, 7060 and 7364 kg/ha, respectively. There is a significant difference among the three farm categories in respect to input energy and agronomical managements such as transplanting date and land preparation. Energy input in fertilizer application was the highest with 73.80, 75.11 and 76.90% of the total energy input in small, medium and large farm, respectively. The net energy values were 82733, 88321 and 93226 MJ/ha, respectively. Energy ratio in small, medium and large farms were 6.58, 7.07 and 7.62, respectively. Large farms had better energy efficiency due to better management of energy resources. Minimizing input energy through increased level of mechanisation will boost rice production in Nigeria.

A Study on the Determination of the Maintenance Energy Requirement in Growing Goats

A Study on the Determination of the Maintenance Energy Requirement in Growing Goats

Standardized ileal digestible amino acids and net energy contents in full fat and defatted black soldier fly larvae meals (Hermetia illucens) fed to growing pigs.

Two experiments were conducted to determine standardized ileal digestibility (SID) of amino acids (AA; Exp. 1) and net energy (Exp. 2) in two black soldier fly larvae meal (BSFLM) samples [full fat (FF; 42.5% crude protein (CP), as-fed) and defatted (DF; 40.8% CP; as-fed)] for growing pigs. Two cornstarch-based diets were formulated with FF and DF BSFLM as the sole sources of AA. A nitrogen-free diet was also used, and the corn starch:sucrose:oil ratio was kept constant among diets to calculate digestible energy (DE) by difference method. In each experiment, pigs were fed 2.8 × estimated maintenance energy requirement. In Exp. 1, eight ileal-cannulated barrows (25.1 ± 0.41 kg initial body weight) were used in a replicated 2 × 2 Latin square design (n = 8). In each period, pigs were adapted to diets for 5 d followed by 2 d of continuous ileal digesta collection for 8 h. The SID of AA were calculated using basal endogenous losses for pigs fed a nitrogen-free diet. In Exp. 2, eight barrows [23.4 ± 0.54 kg initial body weight (BW)] were used in a partially replicated Latin square design (n = 8). In each period, pigs were adapted to diets for 7 d, followed by 5 d of total urine collection and fecal grab sampling. The SID of CP (80.6 ± 1.1%) and Lys (88.0 ± 1.4%) were not different between FF and DF BSFLM. The SID of Arg, Val, Ala, and Pro tended to be less, and the SID of Met tended to be greater for the FF versus the DF BSFLM (P = 0.034, 0.090, 0.053, 0.065, 0.074, respectively). Digestible energy (4,927 vs. 3,941 ± 75 kcal/kg), metabolizable energy (4,569 vs. 3,396 ± 102 kcal/kg), and predicted net energy (3,477 vs. 2,640 ± 30 kcal/kg, using equations from Noblet; 3,479 vs. 2,287 ± 28 kcal/kg, using equations from Blok, respectively) were greater for the FF versus the DF BSFLM (P < 0.05). The apparent total tract digestibility of neutral detergent fiber and acid detergent fiber were greater for the FF versus the DF BSFLM (P ≤ 0.05). Both FF and DF BSFLM had high SID for most AA; however, FF BSFLM was a better source of net energy for growing pigs. Therefore, both FF and DF BSFLM could be used as protein alternatives in growing pig diets.

Determination of energy and protein requirements for maintenance and lactation of Dorper × Hu crossbred sheep

Abstract This study set out to define the energy and protein requirements for maintenance and lactation of Dorper☓Hu crossbred lactating ewes. Eighteen ewes of similar weight (53.37 ± 1.18 kg) were randomly divided into three groups after parturition: ad libitum (AL), IR70 % (intake restricted to 70 % of AL), and IR50 % groups (intake restricted to 50 % of AL). Energy, nitrogen, and carbon balance were calculated by determining the carbon or nitrogen content of orts, feces, urine, milk, CH4, and CO2 samples in digestibility and respiratory trials. Maintenance requirements of net energy [NEm; 257.04 ± 1.15, 252.35 ± 1.08, 244.34 ± 1.15 kJ/kg body weight (BW)0.75/day]; metabolizable energy (MEm; 353.29 ± 3.27, 352.16 ± 3.54, 354.97 ± 2.67 kJ/kg BW0.75/day); net nitrogen (NNm; 326 ± 110, 306 ± 81, 285 ± 77 mg/kg BW0.75/day); and net protein (NPm; 2.03 ± 0.17, 1.91 ± 0.28, 1.78 ± 0.28 g/kg BW0.75/day) were observed on 20th, 50th and 80th day of lactation. Compared with these results, the Wood’s model showed adequate estimates of peak yield (0.88 vs. 0.87 kg/day), but an overestimation of milk yield either side of the peak, and an underestimation of the timing of peak yield compared with the observed milk curve in the current study (4th vs. 3rd week of lactation, respectively). The corresponding NE requirements for lactation (NEL; MJ/kg milk) linearly increased with progressing lactation and were scaled from 3.76 to 4.19 (MJ/kg milk). Additionally, milk yield varied from 1–3 kg daily, and, from 20th to 80th day of lactation, the daily metabolizable protein (MP) requirement for lactation ranged from 141.14–283.43 g/day. The combined results suggest that the estimated MP and ME requirements for lactating Dorper and Hu crossbred sheep fell between the NRC recommendations for lactating ewes suckling a singleton and twin lambs.

Ad Libitum Energy Intake Differences Between a Plant-Based, Low-Fat and an Animal-Based, Low-Carbohydrate Diet: An Inpatient Randomized Crossover Study

Abstract Objectives To investigate differences in ad libitum energy intake when inpatient adults were exposed to diets with equal calories and protein but varied widely in the ratio of carbohydrate to fat. Methods 16 adults without diabetes were admitted to the Metabolic Clinical Research Unit in the NIH Clinical Center for four continuous weeks and were randomized to receive either a plant-based, low-fat (LF) diet or an animal-based, low-carbohydrate (LC) diet for two weeks, followed by the alternate diet for two weeks. The LF diet was ∼75% carbohydrate and ∼10% fat, whereas the LC was ∼10% carbohydrate and ∼75% fat. The LF diet had ∼4-fold more fiber and was ∼60% of the energy density of the LC diet. Both diets were matched for protein and the presented calories were double each subject's maintenance energy requirements, as calculated from their measured resting energy expenditure multiplied by 1.6. Participants received three daily meals, had continuous access to snacks, and were instructed to eat as much or as little as they wanted. Leftovers were weighed to determine food intake. ProNutra software was used to calculate energy and nutrient intake. Results The study enrolled 9 men and 7 women with an age (mean ± SE) of 29 ± 1.7 years and body mass index (BMI) of 27.5 ± 1.5. During exposure to the LF diet, participants consumed 726 ± 84 kcal/d less than during the LC diet (P &amp;lt; 0.0001). The composition of the food intake closely matched the presented diets, with the LF diet consumption of 75.2 ± 0.2% carbohydrate, 10.7 ± 0.2% fat, and 14.0 ± 0.3% protein whereas the LC diet consumption was 9.9 ± 0.1% carbohydrate, 74.5 ± 0.2% fat, and 15.6 ± 0.2% protein. During the second week of the LC diet, when ketosis had been fully established (capillary β-hydroxybutyrate = 1.4 ± 0.08 mM), intake decreased by 295 ± 52 kcal/d compared to the first week (P &amp;lt; 0.0001) whereas during the second week of the LF diet intake was not significantly changed (−51 ± 52 kcal/d; P = 0.33). Nevertheless, energy intake remained 611 ± 68 kcal/d lower during the second week of the LF diet than the LC diet (P &amp;lt; 0.0001). Conclusions Exposure to the LF diet resulted in significantly lower ad libitum energy intake compared to the LC diet, potentially due to its lower energy density and greater fiber content. Funding Sources Intramural Research Program of the National Institute of Diabetes and Digestive and Kidney Diseases.

Energy requirements for maintenance and growth of young pre-ruminant Angora goats

Abstract There is little information available on the nutrient requirements of suckling Angora kids weighing less than 10 kg which has resulted in nutrition recommendations being based on older, heavier and weaned goats. This experiment determined the energy intake of suckling Angora kids to estimate maintenance ME requirement (MEm) and ME required for growth (MEg) for 8 and 21 day old kids. Does were housed in individual pens in an outdoor feedlot from day 47 of pregnancy. Pregnant does experienced a range of controlled nutrition treatments providing a range in live weight and body condition at kidding. From 4 days postpartum treatments were: ad libitum (AL) to allow maximum ME intake resulting in doe live weight gain; or Restricted (R) to 70% of AL, resulting in doe live weight loss until week 10 of lactation. Doe milk production was determined at days 8 and 21 of lactation, and ME intake of milk, kid liveweight change and fibre growth rate were determined. ME intake (kJ/kg0.75day) was then related to daily liveweight gain (g/kg0.75day) using multiple linear regression analysis. At 8 days of age, MEm = 1199 kJ/kg0.75day and MEg = 35.6 kJ/kg0.75day (P = 0.002). At 21 days of age, MEm = 700 kJ/kg0.75day (NS) and MEg = 24.0 kJ/kg0.75day (P

Use of reduced-energy content maintenance diets for modest weight reduction in overweight cats and dogs

One option for controlled weight loss for dogs and cats in overweight condition could be to modestly restrict caloric intake using a reduced-energy (‘light’) maintenance diet, but there is no prior research on the safety and efficacy of such an approach. A prospective observational cohort study was performed in 67 overweight dogs and 17 overweight cats undergoing weight loss using reduced-energy maintenance diets from one manufacturer. Diets were fed at approximately 80% of maintenance energy requirements for ideal bodyweight for a period of 8 weeks. Essential nutrient intake was estimated for each dog and cat and compared with minimum requirement (MR) or adequate intake (AI, when no MR had been demonstrated) as set by the National Research Council in 2006. Weight loss was seen in 56/67 dogs (84%), losing a median of 4.7% (range 15.2% loss to 10.0% gain) of their starting body weight (SBW). Weight loss was also seen in all 17 cats, losing a median of 6.4% (range 2.0 loss to 15.2% loss) of SBW. Of the essential nutrients examined, only selenium, choline, potassium, and riboflavin were less than NRC recommendations in a minority of animals. However, no signs of any nutrient deficiency were observed in any of the dogs or cats during the study. In summary, modestly energy restricting overweight dogs and cats when feeding a low-energy maintenance diet can induce weight loss and might be a useful initial step for weight management. Although no adverse effects were seen, borderline intake of some micronutrients warrants further consideration.