Dietary Crude Protein Content Research Articles

Prediction of nitrogen excretion from data on dairy cows fed a wide range of diets compiled in an intercontinental database: A meta-analysis.

Manure nitrogen (N) from cattle contributes to nitrous oxide and ammonia emissions and nitrate leaching. Measurement of manure N outputs on dairy farms is laborious, expensive, and impractical at large scales; therefore, models are needed to predict N excreted in urine and feces. Building robust prediction models requires extensive data from animals under different management systems worldwide. Thus, the study objectives were (1) to collate an international database of N excretion in feces and urine based on individual lactating dairy cow data from different continents; (2) to determine the suitability of key variables for predicting fecal, urinary, and total manure N excretion; and (3) to develop robust and reliable N excretion prediction models based on individual data from lactating dairy cows consuming various diets. A raw data set was created based on 5,483 individual cow observations, with 5,420 fecal N excretion and 3,621 urine N excretion measurements collected from 162 in vivo experiments conducted by 22 research institutes mostly located in Europe (n = 14) and North America (n = 5). A sequential approach was taken in developing models with increasing complexity by incrementally adding variables that had a significant individual effect on fecal, urinary, or total manure N excretion. Nitrogen excretion was predicted by fitting linear mixed models including experiment as a random effect. Simple models requiring dry matter intake (DMI) or N intake performed better for predicting fecal N excretion than simple models using diet nutrient composition or milk performance parameters. Simple models based on N intake performed better for urinary and total manure N excretion than those based on DMI, but simple models using milk urea N (MUN) and N intake performed even better for urinary N excretion. The full model predicting fecal N excretion had similar performance to simple models based on DMI but included several independent variables (DMI, diet crude protein content, diet neutral detergent fiber content, milk protein), depending on the location, and had root mean square prediction errors as a fraction of the observed mean values of 19.1% for intercontinental, 19.8% for European, and 17.7% for North American data sets. Complex total manure N excretion models based on N intake and MUN led to prediction errors of about 13.0% to 14.0%, which were comparable to models based on N intake alone. Intercepts and slopes of variables in optimal prediction equations developed on intercontinental, European, and North American bases differed from each other, and therefore region-specific models are preferred to predict N excretion. In conclusion, region-specific models that include information on DMI or N intake and MUN are required for good prediction of fecal, urinary, and total manure N excretion. In absence of intake data, region-specific complex equations using easily and routinely measured variables to predict fecal, urinary, or total manure N excretion may be used, but these equations have lower performance than equations based on intake.

Dietary crude protein concentrations, feed grains, and whey protein interactively influence apparent digestibility coefficients of amino acids, protein, starch, and performance of broiler chickens

The present study was designed to investigate the impacts of dietary crude protein (CP) concentrations (220 and 180 g/kg) in either maize- or wheat-based diets, without or with 25 g/kg inclusions of whey powder (WP) concentrate on performance parameters and apparent amino acid digestibility coefficients in broiler chickens. The maize and wheat used in this study had CP levels of 84 and 119 g/kg, respectively. The 2 × 2 × 2 factorial array of 8 dietary treatments was offered to a total of 336 off-sex, male Ross 308 chicks from 7 to 35 d post-hatch with 7 replicate cages (6 birds per cage) per treatment. A treatment interaction (P = 0.016) between dietary CP and feed grains was detected for weight gains, where birds offered 180 g/kg maize-based diets displayed a weight gain advantage of 6.74% (2,628 vs. 2,462 g/bird) compared to their wheat-based counterparts. An interaction (P = 0.022) between feed grains and whey protein was observed for FCR as the addition of WP to maize-based diets improved FCR by 3.45% (1.314 vs. 1.361), but compromised FCR in wheat-based diets by 2.98% (1.415 vs. 1.374). A treatment interaction (P = 0.038) between dietary CP and feed grains was recorded for relative abdominal fat-pad weights weight gains as birds offered 180 g/kg CP maize-based diets had 43.4% (11.17 vs. 7.79 g/kg) heavier fat-pads than their wheat-based counterparts. Following the reduction in dietary-CP, apparent amino acid digestibility coefficients were depressed to greater extents in wheat-based diets. However, significant interactions between CP and feed grains were found in 14 of the 16 amino acids assessed and significant interactions between CP and WP were observed for 15 amino acids. Maize was the more suitable feed grain in terms of weight gain and FCR in 180 g/kg CP diets despite causing greater fat deposition. The inclusion of WP in reduced-CP diets did not enhance bird performance. Data generated indicate concentrations of microbial amino acids in distal ileal digesta were depressing apparent amino acid digestibility coefficients, which was more evident in wheat-based diets. Higher gut viscosities in birds offered wheat-based diets may have facilitated the proliferation of microbiota along the small intestine.

Productive performance ofTenebrio molitor larvae in response to the protein level in the substrate

Insect production for animal feeding is receiving increasing interest worldwide. The dietary protein level is a key factor influencing overall production and feeding costs. Thus, a growth performance trial was conducted withTenebrio molitorlarvae for 28 days using substrate feeds based on wheat grain and barley straw with increasing levels of soybean meal to reach 100 (10P), 120 (12P), 140 (14P) and 160 (16P) g crude protein (CP) per kg dry matter (DM). Four trays per treatment, with 40 larvae and 24 g substrate, were set up. Average mortality was 0.142 and did not differ among treatments. Feed intake decreased linearly (L,P<0.001) and quadratically (Q,P<0.01) and larval growth (mg/d per larvae) tended to decrease (Q,P=0.065) as the dietary CP increased from 100 to 160 g/kg DM. Protein intake, however, increased (L,P<0.001) with the CP content of the diet. Feed to gain ratio decreased (L,P<0.01) as the dietary CP level increased but total production per tray of DM, CP or ether extract, was not affected. In conclusion, an increase in the dietary CP content over 100 g/kg DM by including soybean meal in the substrate might not be needed to optimise larval growth. A CP content in the diet of 100 g/kg might improve the economic results because of lower feeding costs.

Dietary crude protein concentrations and L-carnitine inclusions interactively influence performance parameters of grower broiler chickens offered sorghum-based diets

This study investigated the effects of dietary crude protein (CP) and L-carnitine on the performance of broiler chickens offered sorghum-based diets. In a 3 x 3 factorial array of CP concentrations (220, 190, 160 g/kg) and L-carnitine inclusions (0, 75, 150 mg/kg), dietary treatments were offered to 324 off-sex, male Ross 308 broiler chickens from 7 to 33 days post-hatch. Treatment interactions (P < 0.001) were observed for growth performance parameters with 75 and 150 mg/kg L-carnitine inclusions in 160 g/kg CP diets increasing weight gain by up to 15.9 % (1593 versus 1374 g/bird), feed intake by up to 12.4 % (2492 versus 2218 g/bird) and improved FCR by up to 3.16 % (1.564 versus 1.615). In contrast, L-carnitine inclusions in 230 and 190 g/kg CP diets had negligible impacts on growth performance. Reducing dietary CP compromised growth performance and increased relative abdominal fat-pad weights by 44.1 % (11.44 versus 7.94 g/kg) as main effects but L-carnitine did not influence fat-pad weights. The possibility that growth performance responses observed in birds offered 160 g/kg CP diets may be attributed to L-carnitine counteracting the effects of NH3 intoxication which is given consideration because it has been established that L-carnitine is protective against (NH3) toxicity. Reducing dietary CP significantly increased jejunal and ileal digestibility coefficients of the majority of amino acids; whereas, L-carnitine had negative effects. Also, L-carnitine significantly depressed free plasma concentrations of 13 amino acids but increased concentrations of lysine, methionine, valine and glutamine. The possibility that L-carnitine was competing with amino acids for intestinal uptakes is discussed.

Capping dietary starch: Protein ratios enhances performance of broiler chickens offered reduced-crude protein, maize-based diets

The objective of this study was to determine if capping dietary starch:protein ratios in reduced-crude protein diets enhances growth performance of broiler chickens offered maize-based diets. A total of 288 off-sex, male Ross 308 chickens were offered a 2 × 3 factorial array of dietary treatments from 7 to 35 days post-hatch. Dietary starch:protein ratios were either standard (mean: 2.47) or capped (mean: 2.12) with three dietary crude protein concentrations of 195, 185 and 175 g/kg. Dietary starch:protein ratios were capped by substituting soybean meal with full-fat soy; sourced from the same supplier. The parameters assessed included growth performance, relative abdominal fat-pad weights, nutrient utilisation, excreta nitrogen concentrations, distal jejunal and distal ileal digestibility coefficients and disappearance rates of starch and protein, jejunal and ileal starch:protein disappearance rate ratios, distal jejunal and distal ileal apparent amino acid digestibility coefficients, distal ileal amino acid disappearance rates and free amino acid concentrations in systemic plasma. Capping dietary starch:protein ratios significantly reduced ileal starch:protein disappearance rate ratios in birds offered 195, 185 and 175 g/kg crude protein by 14.6% (2.40–2.05), 13.8% (2.61–2.25) and 29.3% (3.75–2.65), respectively. Capping starch:protein ratios in 175 g/kg crude protein diets significantly improved weight gain by 3.45% (2398 versus 2318 g/bird) and feed conversion ratio by 3.75% (1.360 versus 1.413) and relative abdominal fat-pad weights were numerically lighter by 10.3% (11.47 versus 12.78 g/kg). Condensing ileal starch:protein disappearance rate ratios were quadratically related (P < 0.001) to improvements in weight gain (r = 0.740), feed conversion ratio (r = 0.786) and lighter fat-pad weights (r = 0.650). Reducing dietary crude protein concentrations depressed apparent ileal digestibility coefficients of 15 of the 16 amino acids assessed (P = 0.021 to < 0.001); average coefficients were reduced by 6.74% (0.803 versus 0.861). These compromised amino acid digestibilities probably contributed to the 6.43% inferior weight gains (2358 versus 2520 g/bird; P < 0.001) and 3.05% inferior feed conversion ratio (1.387 versus 1.346; P < 0.001) following the dietary crude protein reduction from 195 to 175 g/kg. A better comprehension of the impacts of reduced crude protein diets on endogenous amino acid flows and accumulations of microbial amino acids in distal ileal digesta needs to be achieved as both factors will influence apparent amino acid digestibility coefficients. Finally, capping dietary starch:protein ratios in 175 g/kg crude protein diets showed distinct promise in this study as both weight gain and FCR were significantly enhanced.

Effects of dietary crude protein concentration on animal performance and nitrogen utilisation efficiency at different stages of lactation in Holstein-Friesian dairy cows

Nitrogen (N) excretion from livestock production systems is of significant environmental concern; however, few studies have investigated the effect of dietary CP concentration on N utilisation efficiency at different stages of lactation, and the interaction between dietary CP levels and stages of lactation on N utilisation. Holstein-Friesian dairy cows (12 primiparous and 12 multiparous) used in the present study were selected from a larger group of cows involved in a whole-lactation study designed to examine the effect of dietary CP concentration on milk production and N excretion rates at different stages of lactation. The total diet CP concentrations evaluated were 114 (low CP), 144 (medium CP) and 173 (high CP) g/kg DM, with diets containing (g/kg DM) 550 concentrates, 270 grass silage and 180 maize silage. During early (70–80 days), mid- (150–160 days) and late (230–240 days) lactation, the same 24 animals were transferred from the main cow house to metabolism units for measurements of feed intake, milk production and faeces and urine outputs. Diet had no effect on BW, body condition score, or milk fat, protein or lactose concentration, but DM intake, milk yield and digestibilities of DM, energy and N increased with increasing diet CP concentration. The effect of diet on milk yield was largely due to differences between the low and medium CP diets. Increasing dietary CP concentration significantly increased urine N/N intake and urine N/manure N, and decreased faecal N/N intake, milk N/N intake and manure N/N intake. Although increasing dietary CP level significantly increased urine N/milk yield and manure N/milk yield, differences in these two variables between low and medium CP diets were not significant. There was no significant interaction between CP level and stage of lactation on any N utilisation variable, indicating that the effects of CP concentration on these variables were similar between stages of lactation. These results demonstrated that a decrease in dietary CP concentration from high (173 g/kg DM) to medium level (144 g/kg DM) may be appropriate for Holstein-Friesian dairy cow to maintain milk production efficiency, whilst reducing both urine N and manure N as a proportion of N intake or milk production.

P172. Effects of dietary crude protein content and resistant starch supplementation on growth performance, histomorphology, and microbial metabolites in weaned pigs

P172. Effects of dietary crude protein content and resistant starch supplementation on growth performance, histomorphology, and microbial metabolites in weaned pigs

An Analysis Different Levels of Crude Protein Content of Concentrate Feed

A research was done to study body performance responses of selected Donggala cows to different dietary crude protein content of concentrate feed. Twenty selected Donggala cows with an initial body weights range of 278.6(36.97) kg were used. The animals also had body condition score of 2.63(0.29), body length of 129.85(6.38) cm, shoulder height of 124.8(5.74) cm, bust of 157.45(8.7) cm, and hip width of 37.83(3.4) cm. The animals were arranged in a 4 x 5 randomized block design with 5 dietary treatments differing in crude protein content of concentrate feed (12, 14, 16, 18 or 20 percent). Animals grouping was based on their initial body weights. During the experiment which lasted for 8 weeks, the animals were fed on a ration consisting of 25 percent elephant grass and 75 percent concentrate mix. Results of the experiment indicated that total and daily animals body weight gain, and changes in body condition scores were significantly affected (P<0.01) by the dietary crude protein content of feed. The highest overall and daily body weight gains were obtained at the crude protein level of 18%, while that of changes in body condition score were obtained at the crude protein level of 18%. The dietary crude protein levels did not affect (P > 0.05) animals body dimension measures. It may be concluded that the best dietary protein content of concentrate feed for an optimum body performance in Donggala cows before mating is 18 percent.

Microbiome-metabolomics analysis of the effects of decreasing dietary crude protein content on goat rumen mictobiota and metabolites.

ObjectiveThe objective of this study was to investigate the effects of decreasing dietary crude protein content on rumen fermentation, mictobiota, and metabolites in goats.MethodsIn an 84-day feeding trial, a total of twelve male Anhui white goat kids with initial body weight 15.9±1.13 kg were selected and randomly classified into two groups, feeding a normal crude protein diet (14.8% CP, NCP) or a low crude protein diet (12.0% CP, LCP). At the end of the experimental trial (on day 84), six animals were randomly selected from each group and were slaughtered to collect rumen fluid samples for the analysis of rumen fermentation parameters, microbiome, and metabolome.ResultsThe concentrations of ammonia-nitrogen, total volatile fatty acid, acetate, and propionate were decreased (p<0.05) in the LCP group in comparison with those in the NCP group. The abundances of genera Prevotella, Campylobacter, Synergistetes, and TG5, which were associated with nitrogen metabolism, were lower (p<0.05) in the LCP group compared with those in the NCP group. The levels of 78 metabolites (74 decreased, 4 increased) in the rumen fluid were altered (p<0.05) by the treatment. Most of the ruminal metabolites that showed decreased levels in the LCP group were substrates for microbial protein synthesis. Metabolic pathway analysis showed that vitamin B6 metabolism was significantly different (p<0.05) in rumen fluid between the two treatments.ConclusionDecreased dietary protein level inhibited rumen fermentation through microbiome and metabolome shifts in goat kids. These results enhance our understanding of ruminal bacteria and metabolites of goat fed a low protein diet.

Effect of decreasing dietary crude protein in fattening calves on the emission of ammonia and greenhouse gases from manure stored under aerobic and anaerobic conditions

Dietary strategies can potentially help to reduce nitrogen (N) emissions and decrease the environmental impact of beef production. This study aimed to evaluate the effects of dietary crude protein (CP) concentration on animal performance, N excretion, and manure N volatilisation of finishing Holstein animals. In a first study, 105 Holstein bulls (BW 344 ± 2.6 kg; age 252 ± 0.9 days) were allocated to eight pens to evaluate the effect of two treatments (medium (M) and low (L), which contained CP 14.5% and 12% on a DM basis, respectively) on performance, and results confirmed that dietary CP decrease did not impair animal growth. In a second study, N excretion study, 24 Holstein heifers (BW 310 ± 5.3 kg; age 251 ± 1.4 days) were distributed randomly depending on the initial BW to three treatments (high (H), M, and L, which contained CP 17%, 14.5% and 12% on a DM basis, respectively). Based on N excretion, urinary N excretion was greater (P < 0.001) in H than in M and L diets, but no differences in faecal N excretion were observed among treatments. A third study with in vitro assays under aerobic and anaerobic conditions was designed to analyse gaseous emissions (volatilisation of N and carbon, C) during the storage stage of manure. Manure, faecal and urine samples, mixed at a ratio of 1:1 (wet weight), were collected during the N excretion study (manure-H, manure-M, manure-L). Under aerobic conditions, manure-M and manure-L showed a delay of 4–5 days in manure ammonia emission compared with manure-H (P < 0.01). Total N content was lower (P < 0.01) in manure-L compared with manure-M and manure-H, but N volatilisation (percentage relative to initial N) in manure-L and manure-M was greater (P < 0.01) than in manure-H. In contrast, the anaerobic N volatilisation was 20 times greater in manure-M and 10 times greater in manure-H compared with manure-L. Under aerobic and anaerobic conditions, the emission of C, as C-CO2 and C-CH4, was greater in manure-L than in manure-H and manure-M. Therefore, the decrease of dietary CP concentration from 17% to 14.5% and 12% is an efficient strategy to reduce urinary N excretion by 40%, without impairing performance, and also to reduce manure N losses through ammonia volatilisation under anaerobic conditions. However, a dietary CP content of 14.5% resulted in less environmental impact than a CP content of 12.8% when also considering manure emissions under aerobic or anaerobic conditions.

Feeding intact proteins, peptides, or free amino acids to monogastric farm animals.

For terrestrial farm animals, intact protein sources like soybean meal have been the main ingredients providing the required amino acids (AA) to sustain life. However, in recent years, the availability of hydrolysed protein sources and free AA has led to the use of other forms of AA to feed farm animals. The advent of using these new forms is especially important to reduce the negative environmental impacts of animal production because these new forms allow reducing the dietary crude protein content and provide more digestible materials. However, the form in which dietary AA are provided can have an effect on the dynamics of nutrient availability for protein deposition and tissue growth including the efficiency of nutrient utilization. In this literature review, the use of different forms of AA in animal diets is explored, and their differences in digestion and absorption rates are focused on. These differences affect the postprandial plasma appearance of AA, which can have metabolic consequences, like greater insulin response when free AA or hydrolysates instead of intact proteins are fed, which can have a profound effect on metabolism and growth performance. Nevertheless, the use and application of the different AA forms in animal diets are important to achieve a more sustainable and efficient animal production system in the future, as they allow for a more precise diet formulation and reduced negative environmental impact. It is, therefore, important to differentiate the physiological and metabolic effects of different forms of AA to maximize their nutritional value in animal diets.

Supplementation of exogenous β-mannanase to low-protein diets improves feed conversion efficiency in lactating dairy cows

Context Supplementation of exogenous enzymes has been used to improve nutrient utilisation and reduce environmental impacts of excess nutrient release to the environment in swine, poultry and, to a lesser extent, ruminant production systems. Aims We aimed to determine effects of supplementation with a fibrolytic enzyme, β-mannanase, on feed conversion efficiency (FCE) and milk yield in cows fed a diet relatively low in crude protein (CP) concentration. Methods Twelve mid-lactation multiparous Holstein cows producing 40.5 ± 3.6 kg milk/day were assigned to three dietary treatments in a three-period crossover design. Treatment sequences were balanced using 3 × 3 Latin squares to mitigate possible carryover effects. Treatments, fed in a total mixed ration, were high CP (16.1%), low CP (14.6%), and low CP supplemented with commercially available β-mannanase at 0.1% of concentrate dry matter (DM). Key results β-Mannanase supplementation did not affect DM intake, milk yield, or milk component yield and composition. Milk urea-nitrogen was significantly lower in cows fed diets with low CP. Somatic cell counts were reduced in cows supplemented with β-mannanase compared with the other treatments. Apparent total tract digestibilities of DM, organic matter, CP, acid and neutral detergent fibre, starch and ash were unaffected by treatment. Cows receiving β-mannanase showed better FCE than those receiving high CP (13.4% improvement, P = 0.003) or unsupplemented low CP (11.0% improvement). Cows receiving β-mannanase used dietary CP more efficiently to synthesise milk protein than cows receiving high CP (milk protein:CP intake, 0.34 vs 0.30). Nitrogen intake was significantly reduced in the low CP treatments, leading to reduced fecal and urinary nitrogen excretions. Conclusion β-Mannanase supplementation at 0.1% of dietary DM improved FCE and lowered somatic cell counts of dairy cows without affecting milk yield or component yield and composition, while reducing nitrogen excretion. There were potential daily savings of US$1.03/cow compared with a high CP diet. Implications Improvement in FCE can be achieved along with reduced dietary CP content and somatic cell counts without compromising milk production through use of β-mannanase, suggesting a potential economic benefit. Furthermore, reductions in nitrogen excretions with low CP diets are beneficial to the environment.

Effect of stage of lactation and dietary starch content on endocrine-metabolic status, blood amino acid concentrations, milk yield, and composition in Holstein dairy cows

Milk yield and composition are modified by level and chemical characteristics of dietary energy and protein. Those factors determine nutrient availability from a given diet, and once absorbed, they interact with the endocrine system and together determine availability of metabolites to the mammary gland. Four multiparous dairy cows in early lactation and subsequently in late lactation were fed 2 diets for 28 d in a changeover design that provided, within the same stage of lactation, similar amounts of rumen fermentable feed with either high (HS) or low starch (LS). All diets had similar dietary crude protein (15.5% dry matter) and rumen-undegradable protein (∼40% of crude protein) content. Profiles of AA were calculated to be similar to that of casein. On d 28, [1-13C] Leu was infused into one jugular vein with blood samples taken at 0, 2, 4, 6, and 8 h, and cows milked at 0, 2, 4, 5, 6, 7, and 8 h from start of infusion. Isotopic enrichments of plasma Leu, keto-isocaproic acid, and milk casein were determined for calculation of Leu kinetics. Data were subjected to ANOVA using the MIXED procedure of SAS (SAS Institute Inc.), with time as repeated factor and cow as the random effect. Dry matter intake within each stage of lactation was similar between groups. Feeding LS resulted in lower blood glucose and greater ratio of bovine somatotropin to insulin. This response was associated with greater blood concentrations of nonesterified fatty acids and β-hydroxybutyrate, which might have contributed to greater milk fat content in LS-fed cows. Except for His, average concentrations of all AA in blood were higher in late than early lactation. Diet did not alter average plasma concentrations of AA. However, for most of the essential AA (particularly branched-chain), the HS diet led to a marked decrease in concentrations after the forage meal, resulting in significant differences between dietary groups in early lactation. In early-lactating cows fed HS, a greater reduction in plasma concentrations at 8 h relative to pre-feeding values (time zero) was observed for Met, Lys, and His, resulting in decreases of 27.9%, 33.6%, and 38.5%, respectively. A higher bovine somatotropin/insulin ratio in early lactation and in cows fed LS could possibly have led to greater breakdown and, consequently, higher AA flux from peripheral tissues. In LS-fed cows, higher mobilization of body fat and protein was confirmed by the greater body weight loss in both stages of lactation. Higher irreversible loss of [1-13C] Leu in early lactation suggested lower protein retention in peripheral tissues during early compared with late lactation. Milk yield, protein output, and composition were similar between groups at both stages of lactation, whereas milk coagulation was faster (lower curd firming rate) and with higher curd firmness in response to feeding HS in late lactation. Overall, data indicated that rate of carbohydrate fermentability in the rumen can modify the availability of metabolites to the mammary gland and consequently modify milk protein coagulation.

GROWTH OF JUVENILES OF THE FAT SNOOK, Centropomus parallelus, IN RESPONSE TO DIETARY LIPID, ENERGY AND PROTEIN

This study evaluated the growth of fat snook Centropomus parallelus in response to the dietary total lipids, gross energy (GE) and crude protein (CP) content. In the 1st experiment, five isonitrogenous diets with 541.7 ± 2.4 g kg-1 CP varied their lipid content in 113, 151, 160, 189 and 200 g kg-1 and GE in 18.8, 19.4, 20.4, 21.2 and 22.2 MJ kg-1, respectively. A total of 300 fish with 6.5 ± 2.4 g were stocked in 30 tanks of 1 m3 under 10 fish m-³ and reared for 96 days. There were no differences in fish final body weight (38.2 ± 12.5 g), daily weight gain (DWG, 0.35 ± 0.04 g day-1) and specific growth rate (SGR, 1.92 ± 0.11 day-1) among dietary treatments. Feed conversion ratio (FCR) was 1.76 ± 0.17 with a protein efficiency ratio of 1.06 ± 0.10. The viscerosomatic (VSI) and visceral fat indices (VFI) raised significantly with an increase in the dietary lipid while the hepatosomatic index (HSI) was unaffected. There was a significant reduction in feed intake as the dietary lipid content reached 189 g kg-1. In a 2nd study, five isolipidic diets (114.4 ± 1.9 g kg-1 lipids) with decreasing levels of CP and GE of 578, 535, 505, 465, and 430 g kg-1 and 20.5, 19.9, 19.4, 18.9, and 18.1 MJ kg-1, respectively, were evaluated. A total of 1,450 fish of 5.8 ± 2.1 g were reared in 30 tanks of 5.8 m³ under 10 fish m-3 for 93 days. Final survival reached 93.5 ± 5.5%. Fish DWG (0.27 ± 0.05 g day-1) and SGR (1.78 ± 0.11 % day-1) did not vary in response to dietary CP. Final body weight significantly reduced while HSI increased in fish fed the 430 g kg-1CP diet compared with fish fed the 578 g kg-1 CP diet. Results of this work indicated that fish between 5.8 g and 40.8 g wet body weight can maximize growth when fed diets containing 113.2 g kg-1 lipids, 540.5 g kg-1 CP and a 34.7 MJ kg-1 energy to protein ratio.&#x0D; Keywords: Centropomus parallelus, fat snook, protein, lipid, energy.

Influence of dietary protein levels on growth, feed utilization, body indices and serum profile of silver moony Monodactylus argenteus

Monodactylus argenteus, is a high-value euryhaline ornamental fish having a good market demand. Information about its nutrient requirement, especially protein, is essential for feed formulation to maintain good health, growth and colouration. A 3-month feeding trial on the fry of this species was carried out to evaluate the effect of varying dietary protein levels on growth, body indices, serum profile, skin carotenoid content and body composition. Hatchery-produced fry (ABW: 0.73 ± 0.08 g) were randomly distributed into 18 glass tanks (90 L water each) in a recirculatory aquaculture system (RAS) @ 10 fry per tank. Five isolipidic micro-diets (75 g kg−1) with graded levels of crude protein (CP) viz. 250 (CP25), 300 (CP30), 350 (CP35), 400 (CP40), and 450 (CP45) g kg−1 were formulated and fed to satiation twice daily. At the end of the trial, weight gain (WG), specific growth rate (SGR) and protein efficiency ratio (PER) of fish fed with CP35, CP40 and CP45 diets were observed to be significantly higher compared to those fed with CP25, and CP30 diets. Protein efficiency ratio (PER) decreased with increased dietary protein levels. The viscerosomatic index (VSI) and hepatosomatic index (HSI), exhibited a decreasing trend as the level of crude protein increased. The IPF was directly proportional to the dietary crude protein content of the diet, the maximum value being obtained in the CP45 treatment. The whole-body crude protein content showed an increasing trend with the increment in dietary protein level up to the CP40 diet and the diet with the highest crude protein exhibited the lowest whole body crude protein content. Analysis of serum profile revealed that serum triglycerides, glucose and protein levels were significantly different (P < 0.05) among the treatments. The group fed with CP40 recorded the highest concentration of carotenoids which was not significantly different from CP30 and CP35 groups. The whole body amino acids profile showed a significant variation in alanine, serine, threonine, glutamine and glycine. Broken-line regression analysis revealed that the optimum dietary protein level was in the range of 325–349 g kg−1 for maximum growth of silver moony fry. Our study revealed that a minimum of 35% protein in the diet of silver moony fry is optimal for improved growth.

Evaluation of dietary crude protein concentrations, fishmeal, and sorghum inclusions in broiler chickens offered wheat-based diet via Box-Behnken response surface design.

The objective of this study was to investigate the impacts of dietary crude protein (CP), fishmeal and sorghum on nutrient utilisation, digestibility coefficients and disappearance rates of starch and protein, amino acid concentrations in systemic plasma and their relevance to growth performance of broiler chickens using the Box-Behnken response surface design. The design consisted of three factors at three levels including dietary CP (190, 210, 230 g/kg), fishmeal (0, 50, 100 g/kg), and sorghum (0, 150, 300 g/kg). A total of 390 male, off-sex Ross 308 chicks were offered experimental diets from 14 to 35 days post-hatch. Growth performance, nutrient utilisation, starch and protein digestibilities and plasma free amino acids were determined. Dietary CP had a negative linear impact on weight gain where the transition from 230 to 190 g/kg CP increased weight gain by 9.43% (1835 versus 2008 g/bird, P = 0.006). Moreover, dietary CP linearly depressed feed intake (r = -0.486. P < 0.001). Fishmeal inclusions had negative linear impacts on weight gain (r = -0.751, P < 0.001) and feed intake (r = -0.495, P < 0.001). There was an interaction between dietary CP and fishmeal for FCR. However, growth performance was not influenced by dietary inclusions of sorghum. Total plasma amino acid concentrations were negatively related to weight gain (r = -0.519, P < 0.0001). The dietary transition from 0 to 100 g/kg fishmeal increased total amino acid concentrations in systemic plasma by 35% (771 versus 1037 μg/mL, P < 0.001). It may be deduced that optimal weight gain (2157 g/bird), optimal feed intake (3330 g/bird) and minimal FCR (1.544) were found in birds offered 190 g/kg CP diets without fishmeal inclusion, irrespective of sorghum inclusions. Both fishmeal and sorghum inclusions did not alter protein and starch digestion rate in broiler chickens; however, moderate reductions in dietary CP could advantage broiler growth performance.

Influence of crude protein content and flint maize processing methods on the performance of early-weaning Nellore calves

AbstractThis study aims to determine the effects of dietary crude protein (CP) content of early-weaned calves; and the influence of flint maize processing methods on intake, total tract nutrient digestibilities and performance of Nellore heifer calves. Fifteen early-weaned Nellore female calves (4 ± 0.5 months; 108 ± 13.1 kg) were used. In phase 1, animals were fed one of the following diets for 112 days: 130, 145 or 160 g CP/kg dry matter (DM). In phase 2, animals received one of the two diets for 84 days: 0.60 dry ground maize grain, 0.30 whole-plant maize silage plus 0.10 mineral-protein supplement or 0.90 snaplage plus 0.10 mineral-protein supplement. In phase 1, intake and digestibility of dietary components were not affected (P &gt; 0.05) by increasing dietary CP content. Daily total urinary nitrogen (N) and urinary urea N increased (P &lt; 0.05) in response to increasing dietary CP content. Animal performance was not affected (P &gt; 0.05) by dietary CP content. In phase 2, maize processing methods did not affect (P &gt; 0.05) intake and digestibility of dietary components as well as animal performance, carcase characteristics and carcase composition. Therefore, based on the current experimental condition, we conclude that dietary CP concentrations of 130 g/kg DM can be indicated for early-weaned Nellore calves. However, more studies are recommended to validate this result and to evaluate concentrations below 130 g CP/kg DM for early-weaned Nellore calves. Moreover, snaplage could be used as an exclusive fibre and energy source for finishing cattle in feedlot.

Feeding Strategies to Reduce Nutrient Losses and Improve the Sustainability of Growing Pigs.

The efficiency of pig production using nutrients has increased over the years. Still, better efficiency of nutrient utilization can be achieved by feeding pigs with diets adjusted to their estimated requirements. An increase in nutrient efficiency of utilization represents economic gains while maximizing environmental performance. The objective of this paper is to review the impact of different methods of diet formulation that provide farm animals with the amount of nutrients to satisfy their needs while minimizing nutrient excretion and greenhouse gas emissions. Diet formulation is one tool that can help to maximize nitrogen and energy utilization by decreasing crude protein content in diets. The use of local feedstuff and non-human-edible products (e.g., canola meal) associated with synthetic amino acid inclusion in the diet are valuable techniques to reduce carbon footprint. Precision feeding and nutrition is another powerful tool that allows not only daily tailoring of diets for maximal nutrient efficiency of utilization but also to reduce costs and improve nitrogen efficiency of utilization. In this review, we simulated through mathematical models the nitrogen and energy efficiency of utilization resulting from crude protein reduction in the diet. An 8% crude protein reduction in the diet can increase nitrogen efficiency of utilization by 54% while costing 11% less than a control diet without synthetic amino acids. The same reduction in crude protein represented a major improvement in available energy due to the decrease of energetic losses linked to protein deamination. Urinary and hindgut fermentation energy losses were 24% lower for pigs fed with low-protein diets when compared to control diets. In terms of modern feeding techniques and strategies, precision feeding and nutrition can decrease nitrogen excretion by 30% when compared to group phase feeding. The benefits of feeding pigs with low-protein diets and precision feeding techniques are additive and might result in a 61% nitrogen efficiency of utilization. There is room for improvement in the way nutrient requirements are estimated in pigs. Improving the understanding of the variation of nutrient utilization among pigs can contribute to further environmental gains.

513 Late-Breaking: Effects of Dietary Protein Content and Crystalline Amino Acid Supplementation Patterns on Gut Health of Weaned Pigs Raised Under Different Sanitary Conditions

Abstract The objective of this experiment was to investigate the effects of dietary crude protein (CP) content and crystalline amino acids (CAA) supplementation patterns on the histomorphology, immune response, and microbial metabolites in weaned pigs under clean (CSC) or unclean sanitary conditions (USC). One hundred forty-four piglets (6.35 ± 0.63 kg BW) were assigned to 1 of 3 diets: a high CP (HCP; 21%) and two low CP (LCP; 18%) diets supplemented with 10 crystalline indispensable amino acids (IAA) to meet all IAA requirements or only 6 IAA (Lys, Met, Thr, Trp, Val, and Ile) to meet IAA requirements except for Leu, His, and Phe. Each treatment had 8 replicates per sanitary condition with 3 pigs per pen. The CSC room was cleaned and washed weekly, whereas the USC room remained unwashed throughout the experiment and had sow manure spread in the pens. Data were analyzed using the MIXED procedure of SAS with orthogonal contrasts. Pigs fed the LCP diets had longer (P &amp;lt; 0.05) jejunal villi and higher villus height to crypt depth ratios than those fed the HCP diet. No significant difference is found in histomorphology between pigs fed LCP diets with different CAA supplementation patterns. Pigs raised under USC had greater (P &amp;lt; 0.05) plasma interleukin (IL)-10 and IL-6 concentrations and reduced (P &amp;lt; 0.05) plasma tumor necrosis factor-alpha concentration. Also, the LCP diets resulted in a greater (P &amp;lt; 0.05) plasma IL-10 concentration. Interactions (P &amp;lt; 0.05) between sanitation and dietary CP content were observed for goblet cell density and acetate and total volatile fatty acids contents in the jejunum. In conclusion, CAA supplementation patterns did not affect gut morphology in weaned pigs. Feeding LCP diets to weaned pigs improved gut morphology and microbial metabolites in jejunum under USC and ameliorated systemic inflammation induced by USC.

Grass/clover silage for growing/finishing pigs – effect of silage pre-treatment and feeding strategy on growth performance and carcass traits

ABSTRACT This study evaluated the influence of feeding strategy and grass/clover silage pre-treatment on pig growth performance and carcass traits. In total, 128 pigs weighing 30–110 kg were fed either a commercial control feed or received silage in a pellet (SP) or in a total mixed ratio (TMR) containing chopped silage (SC) or intensively treated silage (SE). Silage replaced 20% of dietary crude protein content (g/kg). Diet affected weight gain (P = 0.001), with pigs fed the SP diet showing best overall growth performance. Pigs fed the SC diet had the lowest weight gain (P = 0.001), while pigs fed the SE diet performed similarly to those fed the control diet. Carcass weight and dressing percentage differed between the diets (P = 0.016 and P = 0.018), but there was no difference in lean meat content (P = 0.832). The results show satisfactory growth performance and carcass traits, indicating that silage can replace other protein sources in growing/finishing pig diets.