Effects Of Dietary Crude Protein Research Articles

Effect of Dietary Crude Protein, Lysine Level and Amino Acid Balance on Performance of Broilers 0 to 18 Days of Age

The present study was conducted to investigate the effects of dietary Crude Protein (CP), lysine and amino acid balance in male broiler diets on performance (weight gain and feed conversion, feed efficiency, protein efficiency ratio). Five test diet series were used: 1) the 23% CP diet; 2) the 21% CP diet; 3) the 21% CP diet plus additional amino acids (21.68% total CP) to provide at least as much of the essential amino acids as present in the 23% CP diet; 4) the 19% CP diet and 5) the 19% CP diet plus additional amino acids (20.31% total CP) to provide at least as much of the essential amino acids as present in the 23% CP diet. For each of the five test diets series, additional Lys was added to provide total Lys levels of 1.10, 1.15, 1.20, 1.25, 1.30, 1.35 and 1.40%. This resulted in a total of 35 final experimental treatments in a 5 x 7 factorial arrangement. Each treatment was fed to 6 replicate pens of 6 male broilers in electrically heated battery brooders from 1-18 days of age. Birds fed the low-protein diets (21%) supplemented with EAAs (21.68% total CP) showed significantly the highest BW and best FCR and FE. There were no significant differences in BW between birds fed control diet (23%) and 19% CP or 19% plus EAAs (20.31% total CP) and 21% CP. FC and PER were significantly affected by dietary protein levels. FCR and FE were significantly improved and BW increased significantly by increasing dietary lysine levels up to 1.25%. An interactions of CP with or without EAAs with dietary lysine level were significant for BW. FCR, FE, FC and PER not significantly influenced by interaction. Thus, our results suggest that maximum body weight could be obtained with a 21% low-CP plus EAA supplementation which was the same as that of the chicks fed high protein diet (23% CP). Optimum dietary lysine level for performance was affected by dietary protein level and amino acid balance.

Effect of dietary crude protein level on visceral organ mass, cellularity, and the protein expression of ATP synthase, Na+/K+-ATPase, proliferating cell nuclear antigen and ubiquitin in feedlot steers

Twenty-four steers [initial body weight (BW) = 510 ± 4.9 kg] predominately of Angus breeding were used to determine the effect of dietary crude protein (CP) level [8.5, 10.7, 12.3 or 14.5%, dry matter (DM) basis; high-moisture-corn-based diets] on visceral mass, cellularity, and protein expression of ATP synthase, Na+/K+-ATPase, proliferating cell nuclear antigen (PCNA) and ubiquitin. Steers were on dietary treatment for 28 d. Kidney, liver, and reticulorumen weights (g) increased linearly (P < 0.05) with increased dietary CP. Lung weight (g; g kg-1 BW) linearly increased (P < 0.05) with increased CP. Ruminal and small intestinal DNA concentration, and the ratios of RNA:DNA and protein:DNA in small intestine were affected quadratically by increased dietary CP (P < 0.05). Hepatic ATP synthase expression was affected quadratically with an increase when dietary CP increased from 8.5 to 10.7%, and a decrease when dietary CP increased from 10.7 to 14.5% (P < 0.05). Renal ATP synthase expression decreased linearly (P < 0.05) and small intestine mucosal Na+/K+-ATPase expression increased linearly (P = 0.05) with increased CP. These results indicate that increasing dietary CP increases liver, kidney, lung, and rumen masses, and differentially influences expression of proteins influencing energy utilization and efficiency in liver, kidney, and small intestine.Key words: Dietary crude protein, visceral organ mass, cellular energy metabolism, steer

Dietary Protein and Cellulose Effects on Chemical and Microbial Characteristics of Swine Feces and Stored Manure

The objectives of this study were to investigate the effects of dietary crude protein (14.5 or 12.0%) and cellulose (8.7 or 2.5%) levels on composition of feces and manure after 8 wk of diet feeding and storage. Pigs were fed twice daily; after each feeding, urine and feces were collected and added to manure storage containers. On weeks 2 and 8 after initiation of the experiment, fresh fecal and manure samples were obtained. On Week 8, increased dietary cellulose resulted in significantly higher levels of volatile fatty acids (VFA) and phenols in feces compare to other diets. In contrast, dietary protein had the greatest effect on manure chemical composition; lower protein decreased sulfur content, ammonia, and phenolic compound concentrations. High levels of either dietary cellulose or protein tended to increase microbial community similarity in fecal samples, but only high protein increased similarity among manure sample microbial communities. Fecal and manure samples from Week 8 differed from samples taken in Week 2 both in chemical and microbiological composition. Week 2 samples had lower concentrations of many of chemical compounds and microbial diversity than samples from Week 8. The fecal results indicate that after 2 wk of feeding experimental diets the animals were not fully adapted to the diets. More importantly, after only 2 wk of urine and fecal collection, manure was not representative of stored manure, limiting its usefulness in developing standards and recommendations for on-farm management practices.

A meta-analysis of the effects of dietary protein concentration and degradability on milk protein yield and milk N efficiency in dairy cows

Data sets from North American (NA, 739 diets) and North European (NE, 998 diets) feeding trials with dairy cows were evaluated to investigate the effects of dietary crude protein (CP) intake and ruminal degradability on milk protein yield (MPY) and efficiency of N utilization for milk protein synthesis (MNE; milk N ÷ N intake) in dairy cows. The NA diets were based on corn silage, alfalfa silage and hay, corn and barley grains, and soybean meal. The NE diets were based on grass silage, barley and oats grains, and soybean and rapeseed meals. Diets were evaluated for rumen-degradable and undegradable protein (RDP and RUP, respectively) concentrations according to NRC (2001). A mixed model regression analysis with random study effect was used to evaluate relationships between dietary CP concentration and degradability and MPY and MNE. In both data sets, CP intake alone predicted MPY reasonably well. Addition of CP degradability to the models slightly improved prediction. Models based on metabolizable protein (MP) intake predicted MPY better than the CP or the CP-CP degradability models. The best prediction models were based on total digestible nutrients (TDN) and CP intakes. Similar to the MPY models, inclusion of CP degradability in the CP (intake or concentration) models only slightly improved prediction of MNE in both data sets. Concentration of dietary CP was a better predictor of MNE than CP intake. Compared with the CP models, prediction of MNE was improved by inclusion of TDN intake or concentration. Milk yield alone was a poor predictor of MNE. The models developed from one data set were validated using the other data set. The MNE models based on TDN and CP intake performed well as indicated by small mean and slope bias. This meta-analysis demonstrated that CP concentration is the most important dietary factor influencing MNE. Ruminal CP degradability as predicted by NRC (2001) does not appear to be a significant factor in predicting MPY or MNE. Data also indicated that increasing milk yield will increase MNE provided that dietary CP concentration is not increased, but the effect is considerably smaller than the effect of reducing CP intake.

Effects of dietary protein concentration on the efficiency of nitrogen utilisation in lactating dairy cows

The European Union Nitrates Directives set a limit on the amount (170 kg/ha) of manure nitrogen (N, = faecal N + urine N) that may be applied to land each year. This limit has very significant implications for stocking rates on intensive livestock farms. Consequently, there is increasing interest in developing mitigation strategies to reduce N output in faeces and urine in animal production systems. The objectives of the present study were to evaluate the effects of dietary crude protein (CP) concentration on the efficiency of N utilisation in lactating dairy cows.

Effects of dietary protein concentration on energetic efficiency and methane emission in lactating dairy cows

A series of studies have been undertaken to examine effects of dietary protein source and concentration on milk production, energy and nitrogen (N) utilisation efficiencies and fertility in dairy cows. The present study evaluated effects of dietary crude protein (CP) concentration on energetic efficiency and methane emission in lactating dairy cows.

Effects of Dietary Crude Protein on Protein and Fat Deposition in Milk-Fed Veal Calves

Research on veal calf production has focused on maximizing lean tissue growth. Nevertheless, limited attention has been paid to the evolution of digestive and metabolic utilization of N and energy as calves get older, whereas age at slaughter increases. The objective of this study was to determine the effects of 4 concentrations of dietary crude protein (CP) content on protein and fat deposition and energy utilization in milk-fed calves at 3 stages of fattening using the balance technique combined with heat production measurements in a respiration chamber. At each stage, 16 Prim’Holstein male calves (mean body weight at each stage: 72, 136, and 212kg) received 4 isocaloric diets with CP contents of 76, 88, 100, and 112% of a reference CP content fixed at 20% during the first stage and 19% during the 2 later stages. After 2 wk of adaptation to their respective diets and housing conditions, the calves were placed for 1 wk in an open-circuit respiration chamber for N and energy balance measurements (first 6 d) and measurement of the fasting heat production (last day). Measurements for a stage were performed over 2 periods of 4 successive weeks. There was no effect of dietary CP on digestibility during the 2 later stages, but the low-protein diet resulted in lower digestibility coefficients for dry matter, organic matter, gross energy, CP, and crude fat during the first stage. Endogenous fecal N was estimated as 2.5g/kg of dry matter intake irrespective of stage, and metabolic urinary N was estimated at 0.07g/kg of body weight0.85 per day. Maximum N retention was 32.8, 40.5, and 44.0 g/d at stages 1, 2, and 3, respectively. The effect of protein intake on protein deposition was dependent on age of the calves, because the marginal efficiency of digestible protein utilization decreased from 64 to 18% as animals got older. Fat deposition decreased with increasing dietary CP content irrespective of stage. Total energy retention was not modified by dietary CP content. The composition of body weight gain was affected differently for each stage, because the protein content of body weight gain increased with increasing dietary CP content during the first stage, whereas it remained constant during the other 2 stages. Fat and energy content in body weight gain decreased with increasing dietary CP irrespective of stage. These results provide a basis for estimating protein requirement of veal calves according to a factorial approach.

Effects of dietary crude protein and supplemental urea levels on nitrogen and phosphorus utilization by feedlot cattle1

Three dietary CP concentrations (11.5, 13.0, and 14.5% of DM) and 3 supplemental urea levels (100, 50, and 0% of supplemental N) were used in a completely randomized block design experiment conducted at 2 locations to determine N and P balance and serum urea N (SUN) concentrations of feedlot cattle. Crossbred steers [British and British x Continental; initial BW = 315.0 +/- 3.2 kg at location 1 (n = 27) and initial BW = 353.2 +/- 8.4 kg at location 2 (n = 27)] were used in 3 nutrient balance sampling periods (SP) at the beginning, middle, and end of the feeding period (154 d in location 1 and 159 d in location 2). Fecal N (g/d; P = 0.03), urinary N (g/d; P < 0.01), urinary urea N (UUN; g/d; P < 0.01), apparent N absorption (g/d; P < 0.01), and SUN concentration (mg/dL; P < 0.01) increased linearly as dietary CP concentration increased. Nitrogen retention (g/d) was not affected (P = 0.61) by dietary CP concentration. Phosphorus intake (g/d; P = 0.02), fecal P (g/d; P = 0.04), and urinary P (g/d; P = 0.01) increased linearly as dietary CP increased, reflecting changes in diet composition with increasing CP concentrations. As dietary urea levels increased, urinary N (g/d; P = 0.04), UUN (g/d; P = 0.01), and apparent N absorption (g/d; P = 0.04) increased linearly, but P intake (g/d; P = 0.10) and urinary P (g/d; P = 0.02) decreased linearly. No interactions were observed between SP and dietary treatments for most variables. Evaluation of SP means, however, showed that as days on feed increased, fecal N (g/d; P = 0.01), urinary N (g/d; P < 0.01), UUN (g/d; P < 0.01), apparent absorption of N (g/d; P < 0.01), SUN (mg/dL; P < 0.01), and urinary P (g/d; P < 0.01) increased linearly, whereas retained N (g/d) decreased linearly (P < 0.01) with increasing days on feed. These data suggest that changes in dietary CP and urea levels, as well as stage of the feeding period, markedly alter N and P utilization by feedlot cattle.

사료 중 단백질 수준 및 CLA(Conjugated Linoleic Acid) 첨가가 비육돈의 생산성 및 육질특성에 미치는 영향

본 연구에서는 비육돈 사료내 조단백질 및 CLA 수준과 그들간의 상호작용이 성장 및 육질특성에 미치는 효과를 구명하기 위하여 수행하였다. 공시동물은 일령이 비슷하고 체중이 79±1kg되는 3원교잡종 48두를 공시하였다. 처리구는 시료 중 조단백질 함량 2수준(11.3%, 16.0%)과 CLA 함량 2수준(0%, 2.5%)의 2×2 요인실험으로, 처리당 4반복, 반복당 3두씩 완전임의 배치하였다. 종료체중(P<0.05)과 일당증체량(P<0.01)은 조단백질 11.3% 급여구가 16.0% 급여구에 비해 유의적으로 낮았으며, 사료요구율(feed/gain, P< 0.01)은 조단백질 11.3% 급여구가 16.0% 급여구에 비해 유의적으로 높았다. 도체중량은 조단백질 11.3% 급여구가 16.0% 급여구에 비해(P<0.001), CLA 2.5% 첨가구가 CLA 무첨가구에 비해(P<0.01) 유의적으로 낮았다. 조단백질 11.3% 첨가구에서는 CLA의 첨가가 도체중량에 영향을 미치지 않았으나, 조단백질 16.0% 첨가구에서는 CLA 2.5% 첨가 시 도체중량이 유의적으로 감소하여, 조단백질과 CLA간 상호작용이 나타났다(P<0.01). 등지방두께는 조단백질 11.3% 급여구가 16.0% 급여구에 비해, CLA 2.5% 첨가구가 CLA 무첨가구에 비해 유의적으로 낮았다(P<0.05). 조단백질 11.3% 첨가구에서는 CLA의 첨가가 등지방두께에 영향을 미치지 않았으나, 조단백질 16.0% 첨가구에서는 CLA 2.5% 첨가 시 등지방두께가 유의적으로 감소하여, 조단백질과 CLA간 상호작용이 나타났다(P<0.001). 상강도(marbling score) 및 근내지방(intramuscular fat) 함량은 조단백질 11.3% 수준의 사료를 섭취한 시험구가 조단백질 16.0% 수준의 사료를 섭취한 시험구보다 유의적으로 높았다(P<0.01). 결론적으로 비육후기에 저 단백질 사료 급여로 등지방은 얇으면서 기호성이 높은 고 상강도의 돈육생산이 가능할 것으로 사료된다. 한편 정상적인 수준의 조단백질 사료 급여 시 CLA의 첨가로 등지방두께를 낮출 수 있을 것으로 사료된다. This study was conducted to investigate effects of dietary crude protein(CP) level and supplementation of conjugated linoleic acid(CLA) on growth performances and meat quality parameters in finishing pigs. The experiment was designed using protein levels(11.3%, 16.0%) and CLA levels(0%, 2.5%) according to 2×2 factorial design. A total of forty-eight pigs [(Landrace×Yorkshire)×Duroc] with an average initial weight of 79±1kg were allotted to one of four dietary treatments. Each treatment had four replications of three pigs per replicate. Final body weight(P<0.05) and average daily gain(P<0.01) were lower in 11.3% CP treatments than in 16.0% CP treatments, while feed/gain was high(P<0.01) in 11.3% CP treatments compared with 16.0% CP treatments. Carcass weight was lighter in 11.3% CP treatments(P<0.001) and CLA 2.5% treatments(P<0.01) than in 16.0% CP and CLA 0% treatments, respectively. A significant interaction between CP and CLA on carcass weight was observed(P<0.01), where supplementation of 2.5% CLA to finishing diets decreased carcass weight in 16.0% CP treatments, while no difference was found in 11.3% CP treatments. Backfat thickness was thinner in 11.3% CP treatments and CLA 2.5% treatments than in 16.0% CP and CLA 0% treatments, respectively(P<0.05). A significant interaction between CP and CLA on backfat thickness was observed(P<0.001), where supplementation of 2.5% CLA to finishing diets decreased backfat thickness in 16.0% CP treatments, while no difference was found in 11.3% CP treatments. Marbling score and intramuscular fat contents were higher in 11.3% CP treatments than in 16.0% CP treatments(P<0.01). In conclusion, feeding of protein-deficient diets in finishing pigs could produce favorable pork with high marbling score and thinner backfat. On the other hand, supplementation of CLA was considered to decrease backfat thickness when diets with optimal level of crude protein were fed to finishing pigs.

Odour and ammonia emission from pig manure as affected by dietary crude protein level

The objective of this study was to determine the effects of dietary crude protein (CP) level on odour emission, odour intensity, odour hedonic tone, ammonia and greenhouse gaseous emission from pig manure, and on fresh faeces and manure characteristics. An experiment was conducted with finishing pigs ( n = 12) in a randomized complete block arrangement with 2 treatments of 12 and 15% dietary CP in six blocks. The 2 diets were supplemented with essential AA up to the level of the animal's requirement. Pigs with an initial body weight (BW) of 57.7 ± 0.7 kg were penned individually in partly slatted floor pens. Faeces and urine of each pig accumulated in separate manure pits under the slatted floor. In the 3rd week of the collection period, fresh faeces were collected for identifying fresh faeces characteristics and for assessing dry matter, organic matter, nitrogen (N), fat and non-starch polysaccharides digestibility using Cr 2O 3 as a marker. In the 6th week of the collection period, air samples were collected directly from each manure pit: one for odour, one for ammonia concentration and one for greenhouse gases. Afterwards the manure was mixed and a representative sample was taken for manure characteristic analysis. Odour samples were analyzed for odour concentration and for hedonic tone and odour intensity. Manure samples were analyzed for volatile fatty acids (VFA), indolic, phenolic, sulphurous compounds, ammonium and total N concentrations and pH. Reducing dietary CP level from 15 to 12% did not affect odour emission, odour intensity and odour hedonic tone and greenhouse gaseous concentration (CH 4, CO 2 and N 2O) ( P > 0.05) of odorous air above the manure pit. Reduced dietary CP level decreased manure pH ( P < 0.001), total N ( P < 0.001) and ammonium ( P < 0.001) concentrations and ammonia emission from pig manure ( P = 0.03). In addition, total VFA, acetic, propionic, iso-butanoic and iso-pentanoic acids, phenol, 4-ethyl phenol and carbon disulfide concentrations in manure were decreased by reducing dietary CP level ( P < 0.05). We conclude that reducing dietary CP from 15 to 12% did not reduce odour emission and greenhouse gaseous concentration; however, ammonia emission was significantly reduced.

Effect of Dietary Protein Intake on Turnover and Oxidation Rates of Plasma Glucose in Adult Sheep

Sano, H., Kajita, M. and Fujita, T. 2007. Effect of dietary protein intake on turnover and oxidation rates of plasma glucose in adult sheep. J. Appl. Anim. Res., 31: 177–180. An isotope dilution method of [U-13C]glucose with open circuit calorimetry was applied to determine the effect of dietary crude protein (CP) intake 5.6, 7.7 and 10.8 g/kg BW0.75 Id on turnover and oxidation rates of plasma glucose in four adult sheep. Isotopic enrichments of plasma [U-13C]glucose and exhaled 13CO2 were determined for calculating the parameters of plasma glucose metabolism. Turnover and oxidation rates of plasma glucose did not change with dietary CP intake levels. It is likely that in adult sheep, plasma glucose metabolism is not influenced by dietary CP intake, when sufficient digestible energy is supplied.

Interactive effects of dietary crude protein and fermentable carbohydrate levels on odour from pig manure

The objective of this study was to determine the effects of dietary levels of crude protein (CP) and levels of fermentable carbohydrates (FC) and their interaction on odour emission, odour intensity, odour hedonic tone, and ammonia emission from pig manure, and manure characteristics. An experiment was conducted with finishing pigs ( n = 36) in a 2 × 3 factorial randomized complete block arrangement with 6 treatment combinations in 6 blocks. There were 2 dietary CP levels (low 12%; high 18%) and 3 digestible FC levels: (low 95.5; medium 145.5; and high 195.5 g/kg feed, as-fed basis). Pigs with an initial body weight (BW) of 57.7 ± 2.5 kg were penned individually in partly slatted floor pens. Faeces and urine of each pig accumulated in separate manure pits under the slatted floor. In the 6th week of the collection period air samples were collected directly above the manure in each pit. Manure samples were taken for manure characteristics. Air samples were analyzed for odour concentration and for hedonic tone and odour intensity. Manure samples were analyzed for volatile fatty acids (VFA), indoles, phenoles, sulphurous compounds, ammonium, and total N concentrations. Dietary CP level and FC level did not affect odour emission, odour intensity and hedonic tone but their interaction affected odour emission at P = 0.06. At a high dietary CP level, increased FC level decreased odour emission, while at a low CP level, increased FC level increased odour emission from pig manure. Total N and ammonium concentrations, and ammonia emission from pig manure were reduced at low dietary CP level ( P < 0.001). High FC level led to low ammonia emission from pig manure ( P = 0.01). Manure pH increased at high dietary CP level ( P < 0.001) and decreased when FC level increased ( P < 0.05). Total VFA concentration increased at high dietary CP level ( P < 0.001) and when FC level increased ( P < 0.001). Enhanced dietary CP increased the manure concentrations of phenol (P < 0.001), cresols ( P = 0.01), indole ( P < 0.001), 4-ethylphenol ( P < 0.001) and carbon disulfide ( P < 0.001), but FC did not affect concentrations of these compounds ( P > 0.05) in the manure. We conclude that the interaction between dietary CP and FC plays a role in odour production and emission. Ammonia emission from pig manure can be reduced substantially by decreasing dietary CP and by increasing FC.

Effect of Dietary Crude Protein and Energy on Gosling Growth Performance and Carcass Trait

The study was undertaken to assess dietary CP and ME concentrations for optimum growth performance and carcass characteristics of goslings. In a 5 × 3 factorial arrangement, 360 one-day-old commercial generation Huoyan goslings were randomly assigned to experimental diets with 10.87, 11.37, 11.87, 12.37, and 12.87 MJ of ME/kg of diet; each contained 15.0, 17.5, and 20.0% CP, respectively, from 0 to 4 wk of age (WOA). Each dietary treatment was replicated 6 times. Body weight and feed consumption were measured, and carcass characteristics were evaluated at 4 WOA. The result showed that birds on a diet with 11.87, 12.37, and 12.87 MJ of ME/kg at 0 to 4 WOA exhibited greater BW gain than those on a diet with 10.87 and 11.37 MJ of ME/kg (P < 0.01), though BW gain was not different among 11.87, 12.37, and 12.87 MJ of ME/kg of diet. Mean BW gain of birds fed 17.5 and 20.0% CP diets was not different (P > 0.05), but they were higher than those on 15.0% dietary CP concentration (P < 0.001). Feed intake was not influenced by dietary ME levels (P > 0.05). Feed intake of birds fed 17.5 and 20.0% CP diets was higher than those of birds on 15.0% CP diets (P < 0.01). Feed conversion ratios of birds fed on 11.87, 12.37, and 12.87 MJ of ME/kg of diet were better than those fed on 10.87 and 11.37 MJ of ME/kg (P < 0.001). Feed conversion ratios of birds fed on 17.5 and 20.0% CP diets were better than those fed on 15.0% CP diets. Moreover, there were no significant interactions between CP and ME on growth performance. There was a direct relationship between dietary ME levels and eviscerated carcass percentage, abdominal fat percentage, and liver relative weight (P < 0.01). Breast and leg meat percentage were influenced by dietary CP concentrations significantly (P < 0.001). Thus, diets with 11.87 MJ of ME/kg and 17.5 to 20.0% CP were used more efficiently from 0 to 4 WOA by Huoyan goslings.

Effects of dietary crude protein level on odour from pig manure

The objective of this study was to determine the effects of dietary crude protein (CP) level on odour emission, odour intensity, hedonic tone, and ammonia emission from pig manure and on manure composition (pH, total nitrogen, ammonium, volatile fatty acids, indolic, phenolic and sulphur-containing compounds). An experiment was conducted with growing pigs (n = 18) in a randomised complete-block design with three treatments in six blocks. Treatment groups were 12%, 15% and 18% CP diets. Barley was exchanged for soya-bean meal. Crystalline amino acids (AA) were included in the 12% CP diet up to the level of pigs' requirement; the same amount of AA was added to the 15% and 18% CP diets. Pigs with an initial body weight (BW) of 36.5 ± 3.4 kg (mean ± s.d.) were individually penned in partly slatted floor pens and offered a daily feed allowance of 2.8 × maintenance requirement for net energy (NE: 293 kJ/kg BW0.75). Feed was mixed with water, 1/2.5 (w/w). Faeces and urine of each pig were accumulated together in a separate manure pit under the slatted floor. After an adaptation period of 2 weeks, the manure pits were cleaned and manure was collected. In the 5th week of the collection period, air samples for odour and ammonia analyses, and manure samples were collected directly from each manure pit. Air samples were analysed for odour concentration and for hedonic value and intensity above odour detection threshold. Manure samples were analysed for volatile fatty acids, and indolic, phenolic and sulphurous compounds, ammonium and total nitrogen concentrations. Reducing dietary CP from 18% to 12% lowered odour emission ( P < 0.05) and ammonia emission ( P = 0.01) from pig manure by 80% and 53%, respectively. Reduced dietary CP decreased total nitrogen, methyl sulphide, carbon disulphide, ethanethiol, phenol, 4-ethyl phenol, indole and 3-methyl indole concentrations in the manure ( P < 0.05). Volatile fatty acids and cresols concentrations in the manure of pigs fed different dietary CP levels were similar. A reduction of dietary CP and at the same time providing essential AA is an option to reduce odour emission as well as ammonia emission from pig manure.

RESPONSE OF LAYING HENS TO DIETS SUPPLEMENTED WITH MICROBIAL PHYTASE AND DIFFER IN THEIR PROTEIN AND METHIONINE CONTENT.

A total number of 480 Bovans White laying hens 21 weeks of agewere used to study the effect of dietary crude protein (CP), methionine (M)and microbial phytase (Phy) levels on laying hen performance, egg shellthickness, nutrient digestibility coefficients and economic efficiency.Hens were randomly divided into 8 equal groups with four replicates of15 hens each. Two levels each of crude protein, methionine and microbialphytase were used in a 2X2X2 factorial design. The two levels of crudeprotein were the optimum level, 18% (CP

Response of broiler chickens to different dietary crude protein and feeding regimens

Five isocaloric (3200kcal/kg) diets were used in an experiment designed to investigate the effects of dietary crude protein (CP) and feeding regimens on broiler performance. Day-old broilers were randomly distributed into four groups using a completely randomized design. Each group was replicated three times with ten broiler chicks per replicate. The experiment lasted for eight weeks. Broilers in group 1 received 23% CP from 0 to 3 weeks, 20% CP from 3 to 6 weeks and 18% CP from 6 to 8 weeks, while broilers in group 2 received 23% CP between 0 and 6 weeks and 18% CP between 6 and 8 weeks. Besides, broilers in group 3 were fed 23% CP from 0 to 4 weeks and 16% CP from 4 to 8 weeks, whereas group 4 was given 18% CP from 0 to weeks. Water was supplied ad libitum for broilers in the different dietary groups. A metabolic trial was carried out on the third week of the experiment using a total collection method. Proximate analyses of diets and faecal samples were performed according to the methods outlined by the Association Of the Official Analytical Chemists. Results at market age showed that broiler performance with respect to feed intake, weight gain, feed to gain ratio and water intake were not significantly influenced by CP regimens (p>0.05). Furthermore, CP regimens did not significantly influence broilers liveability (p>0.05). Protein retention, fat utilization and available fiber were not significantly influenced among treatments (p> 0.05). Economic data showed that cost to benefit ratio of producing broilers was comparable among broilers for all CP regimens used in this trial (p>0.05). It was concluded that a single diet of 18% CP and 3200kcal/kg metabolizable energy would be most suitable and convenient for farmers who are engaged in on-farm feed production for broilers as compared with the standard feeding regimens of broiler starter and broiler finisher diets.

Effects of Glycine and Threonine Supplementation on Performance of Broiler Chicks Fed Diets Low in Crude Protein

A study was conducted to evaluate effects of dietary crude protein (CP) level and Gly and Thr supplementation on performance of male broiler chicks during the period of 0 to 21 days. Diets were formulated based on NRC (1994) recommendations (Lysine at 110% of suggested level). All diets were formulated to contain 3,200 ME kcal/kg. A minimum dietary electrolyte balance of 250 meq/kg was stipulated with a minimum of 0.25% sodium and 0.20% chloride. Five primary diets were formulated to contain 16%, 18%, 20%, 22%, and 24% CP. The diets were then supplemented with additional 0, 0.2%, 0.4% Gly or 0, 0.2%, 0.4% Thr in all possible combinations resulting in a 5x3x3 factorial arrangement. Each of the 45 treatments was fed to six replicate pens of five male commercial broilers. The test diets and tap water were provided for the ad libitum consumption from 1 to 21 d of age. At 21 d of age body weight and feed consumption were determined. Reducing dietary protein below 22% significantly reduced 21 d BW and depressed feed conversion. Addition of 0.2 or 0.4% Gly significantly improved BW and numerically improved feed conversion at lower levels of protein but at protein levels of 20% or more the basal diets appeared to provide sufficient Gly. These data suggest that requirements for Gly suggested by NRC (1994) are inadequate in diets with low CP. Thr supplementation was ineffective in improving performance at low CP levels suggesting that the present recommendations of NRC (1994) are adequate. Mortality did not vary significantly among chicks receiving all experimental diets.

Effect of Dietary Crude Protein and Lysine on Feather Growth in Chicks to Twenty-One Days of Age

A study was conducted to evaluate feather development in male broiler chickens fed variable levels of dietary CP and lysine. Diets contained 170, 210, 250, or 290 g of CP/kg with 0.86, 1.22, 1.34, or 1.46% lysine, each being fed to 2 replicate groups of 4 chicks. Dietary CP per se had a significant effect on feather weight and feather nitrogen gain. Increasing dietary CP from 170 to 250 g of CP/kg of diet increased feather weight and feather nitrogen gain. No differences were found at higher dietary CP levels. Dietary lysine levels from 0.86 to 1.46% did not affect feather weight, feather nitrogen gain, or feather:body weight in male chicks to 21 d. However, feather weight and feather nitrogen gain decreased as lysine increased in diets with 170 and 210 g of CP but not with 250 or 290 g of CP/kg. Percentage of total feather nitrogen was also influenced by the level of dietary lysine in diets containing 210 and 250 g of CP/kg. Feather development was more influenced by dietary CP per se than by levels of lysine.

Effect of dietary protein intake on plasma leucine flux, protein synthesis, and degradation in sheep

Combined experiments of an isotope dilution method of [1- 13C]leucine with open circuit calorimetry and a nitrogen (N) balance test were applied to determine the effect of dietary crude protein (CP) intake on plasma leucine flux and protein synthesis and degradation in four sheep. The experiment was conducted in a 3×4 Latin rectangle design of three 3-week periods. Dietary CP intake was 5.6, 7.7, and 10.8 g/(kg 0.75×d). Metabolizable energy intake was 120% of requirement for all dietary treatments. [1- 13C]Leucine was intravenously infused for 8 h and blood and breath samples were collected during the latter 2-h period of infusion. Isotopic enrichments of plasma [1- 13C]leucine, α-[1- 13C]ketoisocaproic acid, and exhaled 13CO 2 were determined. For the N balance test, N digestibility, N excretion in urine, and protein balance (N×6.25) increased with increasing dietary CP intake. Rates of plasma leucine turnover, protein synthesis, and degradation changed toward reduction with increased dietary CP intake. It is likely that in sheep, high CP intake enhances protein deposition with reduced protein degradation rather than increased protein synthesis.

The effect of protein intake on performance of cows in hot environmental temperatures.

Two trials were conducted with cows in commercial herds during midlactation to evaluate the effect of dietary crude protein (CP) concentration on the production, composition, and efficiency of milk production under hot ambient conditions. Cows were group-fed in trial 1, which was conducted in two herds, and were fed individually in trial 2. The respective average ambient temperature, relative humidity, and temperature-humidity index (THI) were 31 degrees C, 45%, and 78 in trial 1 and 27 degrees C, 70%, and 76 in trial 2. Cows were cooled by forced evaporative means six times daily in trial 1 and three times daily in trial 2. Dietary CP was 15.3 or 17.3% of dry matter (DM) in trial 1 and 15.1 or 16.7% of DM in trial 2. The respective ratios of rumen-degradable organic matter (RDOM) to rumen-degradable protein were 5.3 and 4.8 for the low CP (LP) and high CP (HP) diets. Average DM intake, milk yield, and milk fat and protein concentrations were 22 and 23 kg/d, 34 and 35 kg/d, 3.1 and 3.4%, and 3.2 and 3.1% in trials 1 and 2, respectively, and were similar among diets in both trials. The resultant calculated milk protein efficiency ratio and overall CP efficiency were 0.31 and 0.32 for the LP diets and 0.28 and 0.29 for the HP diets. In cows fed the LP diet, diet rumen ammonia was lower in trial 1, and milk urea N was lower in trial 2. The BW change was higher in trial 1, and tended to be higher in trial 2, with the LP diets. Changes in body condition score in trials 1 and 2 tended to be higher with the LP diets. It was concluded that a dietary CP content of 15.3% is adequate to maintain production in heat-exposed dairy cows producing 35 kg of milk/d, provided that the forced evaporative cooling and the ratio of RDOM to rumen-degradable protein is appropriate