Effects Of Crude Protein Levels Research Articles

116 Effect of Crude Protein Level and a Fermentation Product on Sow Reproductive and Piglet Performance

Abstract High crude protein (CP, greater than 16%) has traditionally been used in lactating sow diet for milk production. However, excess protein can lead to increased gut permeability and inflammation, resulting in compromised reproductive performance. It was hypothesized that decreased dietary CP, using a fermentation product (FER) or addition of Zinc in the lactation diet would promote better gut health and improve sow reproductive performance. The present study was a randomized block design with 5 treatments, 4 of which formed a 2 x 2 factorial arrangement. Gestating sows (n = 550) were enrolled with entry body weight of 209.1 ± 11.4 kg and allotted to one of the following five diets: high CP, no FER; high CP, FER; low CP, no FER; low CP, FER; high CP, ZnSO4 diet. Corn-soy based lactation diet was formulated with high (17.5%) and low (14.5%) CP and with or without FER. High CP with ZnSO4 (360 ppm) was used as a positive control and the added Zn level in the other diets was kept at 120 ppm. All diets were formulated to be at similar net energy and standardized ileal digestible (SID) Lysine (Lys) level with balanced essential amino acid to Lys ratio, except SID isoleucine/Lys was greater in high CP diets. Experimental diets were fed beginning approximately 4 days before farrowing and throughout the entire lactation phase (21 days). Using R, performance data were analyzed using a general linear model and a generalized linear model specifying a binomial distribution was deployed for count data. In summary, dietary treatment did not impact average daily feed intake. Low CP diet resulted in lighter sow weaning weight compared with high CP diet (P < 0.01) and tended to increase piglet average weaning weight (P < 0.10) regardless of FER inclusion. Dietary treatment did not affect the probability of still born or number of weaned pigs. There was an interaction (P < 0.05) between CP and FER on probability of born alive, with low CP, FER diet numerically having greatest probability of born alive. Both low CP (P < 0.10) and high CP with ZnSO4 (P < 0.10) tended to increase livability compared with high CP diet treatment, respectively. High CP with ZnSO4 treatment decreased pre-weaning mortality as compared with high CP treatments (P < 0.05). Conclusively, lower dietary CP led to better reproductive performance in sows and greater piglet weaning weight. The fermentation product did not impact sow or piglet performance as hypothesized, and ZnSO4 used at moderate level in high CP diet reduced pre-weaning mortality.

Dietary protein levels during 12 to 26 wk improve the growth performance, bone quality, and testosterone in Pearl Gray male guinea fowl (Numida meleagris)

Guinea fowl (Numida meleagris), although native to Africa and despite its many potentials, does not represent the dominant species on the continent because of its seasonal reproductive nature and high keets mortality. This study was conducted to assess the effect of crude protein levels on growth performance, bone characteristics and reproductive activity of Pearl Gray male breeder guinea fowl from 12 to 26 wk of age. A total of 120 twelve-wk-old guinea fowls were randomly allotted to 3 dietary treatments with 8 replicates each and 5 birds per replicate using a completely randomized design. The dietary treatments comprised low level (LL), normal level (NL), and high level (HL) with diets respectively containing 15, 17, and 19% crude protein (CP). The results showed that guinea fowl in the HL treatment had a significantly lower feed conversion ratio (P=0.008) than those in the other treatments. The birds fed the HL diet had significantly higher concentrations of testosterone (P < 0.05) than in the other treatments. High levels of calcium and phosphorus were observed in the femur of the HL group relative to the LL group. The birds in the LL treatment had a significantly higher (P=0.007) femur robusticity index than those in the HL treatment. In conclusion, feeding 19% crude protein to Pearl Gray male guinea fowl from 12 to 26 wk of age improves growth performance, the density and strength of the femur and tibia and the reproductive tract. The CP level for the best performance of male guinea fowl from 12 to 26 wk of age is 19%.

Effects of dietary crude protein levels in the concentrate supplement after grazing on rumen microbiota and metabolites by using metagenomics and metabolomics in Jersey-yak.

The crude protein level in the diet will affect the fermentation parameters, microflora, and metabolites in the rumen of ruminants. It is of great significance to study the effect of crude protein levels in supplementary diet on microbial community and metabolites for improving animal growth performance. At present, the effects of crude protein level in supplementary diet on rumen fermentation parameters, microbial community, and metabolites of Jersey-Yak (JY) are still unclear. The purpose of this experiment was to study the appropriate crude protein level in the diet of JY. The rumen fermentation indexes (volatile fatty acids and pH) were determined by supplementary diets with crude protein levels of 15.16 and 17.90%, respectively, and the microbial community and metabolites of JYs were analyzed by non-target metabonomics and metagenome sequencing technology, and the changes of rumen fermentation parameters, microbial flora, and metabolites in the three groups and their interactions were studied. The crude protein level in the supplementary diet had significant effects on pH, valeric acid, and the ratio of acetic acid to propionic acid (p < 0.05). The protein level had no significant effect on the dominant microflora at the phylum level (p > 0.05), and all three groups were Bacteroides and Firmicutes. The results of metabolite analysis showed that the crude protein level of supplementary diet significantly affected the metabolic pathways such as Bile secretion and styrene degradation (p < 0.05), and there were different metabolites between the LP group and HP group, and these different metabolites were related to the dominant microbial to some extent. To sum up, in this experiment, the effects of crude protein level in supplementary diet on rumen microorganisms and metabolites of JY and their relationship were studied, which provided the theoretical basis for formulating a more scientific and reasonable supplementary diet in the future.

In Vitro Rumen Fermentation and Post-Ruminal Digestibility of Sorghum-Soybean Forage as Affected by Ensiling Length, Storage Temperature, and Its Interactions with Crude Protein Levels.

The study aimed to evaluate the effects of ensiling length, storage temperature, and its interaction with crude protein (CP) levels in sorghum−soybean forage mixtures on in vitro rumen fermentation and post-ruminal digestibility of nutrients. The dietary treatments consisted of fresh forages (d 0) and silages of sorghum and soybean stored indoors or outdoors for 75 and 180 d with additional ingredients to make two dietary CP levels, 90 and 130 g/kg dry matter (DM) and a forage-to-concentrate ratio of 80 to 20. An in vitro procedure was conducted using the ANKOM RF technique to study rumen fermentation. The dietary treatments were incubated in duplicate for 8 and 24 h in three runs. After each incubation time, in vitro rumen fermentation parameters were measured, and the protozoa population was counted using a microscope. Post-ruminal digestibility was determined using the pepsin and pancreatic solubility procedure. Cumulative gas production (GP) increased quadratically with ensiling length (8 h, p < 0.01; 24 h, p = 0.02), and the GP differed between CP levels at both incubation times (p < 0.01). However, total short-chain fatty acid (SCFA) concentrations in rumen inoculum increased quadratically with ensiling length (p < 0.01; for both incubation times), and interaction between ensiling length and CP levels was observed in proportions of acetate and propionate after 24 h of incubation (p < 0.01; for both incubation times). Similarly, an interaction between ensiling length and CP levels was found in the proportion of valerate after 24 h of incubation (p < 0.01). There was a quadratic response to ensiling length in the NH4−N concentration after 8 h (p < 0.01) and 24 h (p < 0.05), and the CP level also differed (p < 0.01) at both incubation times. The ciliate protozoa count after 24 h was higher in low CP diets than in high CP diets (p = 0.04). The amount of CP in the undegraded substrate at both incubation times differed between CP levels (p < 0.01; for both incubation times). An interaction effect between ensiling length and storage temperature after 8 h (p = 0.02) and 24 h (p < 0.01) was observed for intestinal CP digestibility. The effect of CP levels on intestinal CP digestibility differed after 8 h (p < 0.01) and 24 h (p < 0.01). In conclusion, increasing ensiling length beyond 75 d reduced CP digestibility, and additional CP inclusion did not ameliorate this.

Effect of crude protein level in high grain diets on calf growth and feed utilization

This study assessed the effect of crude protein level in the diet on animal performance, feed conversion ratio and N utilization, in early-weaned lot-fed calves. Four iso-energetic rations were formulated (ME: 12.0 MJ/kg dm) differing in the crude protein content (CP: 12%, 15%, 17% and 21%, DM basis), and offered in a random experimental design to 24 Hereford calves (107.2 ± 21.5 kg). Animals were individually housed and fed ad libitum twice a day for 84 days. Increasing CP levels in the diet promoted a quadratic response (P&lt;0.01) for dry matter intake (kg/d) and liveweight gain (LWG, kg/d), with maximum LWG of 1.36 kg/d for CP= 17.5%, without differences in subcutaneous back fat thickness (3.70 ± 0.73 mm, P = 0.25) or feed conversion ratio (4.44 ± 0.26, P&gt; 0.10). As CP increased in the diet, N consumption increased quadratically (P &lt;0.01), and an improvement was observed for CP (P = 0.053) and ndf (P = 0.020) apparent digestibility. Daily excretion of N in feces tended to decrease (P = 0.06), while urea-N concentration both in blood (P = 0.013) and urine (P = 0.046) increased. These results show that a level of 17% CP in the diet would optimize the performance of lot-fed early-weaned beef calves while controlling the excretion of N to the environment.

Effect of Crude Protein Level and Coarse Wheat Bran on Nursery Pig Growth Performance

Two experiments were conducted to determine the effect of adding coarse wheat bran with reduced crude protein level in diets without pharmacological levels of zinc oxide on the growth performance and fecal dry matter of nursery pigs. Our objective was to determine if a low-crude protein diet with an added fiber source might provide similar growth performance and reduce the incidence of scours in weanling pigs compared to a typical, high-protein diet with added Zn. A total of 300 and 350 pigs (DNA 241 × 600), initially 15.4 and 13.7 lb body weight (BW), were used in Exp. 1 and 2, respectively. There were 5 pigs per pen and 12 and 14 replicates per treatment in Exp. 1 and 2, respectively. After weaning, pigs were fed a common pelleted diet with phar­macological levels (3,000 ppm Zn) of ZnO for 10 d in Exp. 1, and without pharmaco­logical levels of ZnO for 14 d in Exp. 2. Then, pens were assigned to one of 5 dietary treatments in a randomized complete block design with BW as the blocking factor. In Exp. 1 and 2, treatment diets were offered in mash form and in one dietary phase. All dietary treatments contained 4% coarse wheat bran and consisted of: 1) positive control with ZnO (2,000 ppm Zn) and 21% crude protein (CP) formulated to 1.35% standardized ileal digestible (SID) lysine; 2) a diet with 110 ppm added Zn and 21% CP (1.35% SID lysine); 3) a diet with 110 ppm added Zn formulated to 18% CP (1.20% SID lysine); 4) an 18% CP diet with 110 ppm added Zn formulated to 1.35% SID lysine by the addition of feed grade amino acids; and 5) diet 4 with the addition of non-essential amino acids (glycine and glutamic acid). A common post-treatment pelleted diet was fed for 14 d in Exp. 2 but not in Exp. 1. Data were analyzed using the lmer function from the lme4 package in R. In Exp. 1, pigs fed diets with 21% CP had increased (P < 0.05) ADG and heavier (P < 0.05) final BW; however, treatment means did not separate when Tukey adjustment was applied during statistical analysis. Pigs fed diets with 21% CP had improved (P < 0.05) feed efficiency similarly to pigs fed 18% CP diets with the addition of non-essential amino acids. During the experimental period in Exp. 2, pigs fed high CP diets

Effects of Crude Protein Levels and Binders on Feed Buoyancy

The research determined the effects of crude protein levels and selected natural binders (Cassava, Corn, Rice and Yam) on feed floatability. Eight (8) diets each were prepared at 30%, 35%, 40%, 45% crude protein level. Four parts each of the diets were incorporated with raw and gelatinized binders at appropriate inclusion levels. The results obtained were significantly different (p<0.05) for inclusion levels of crude protein and pellets floatability. Cassava binder gave the best floatability percentage of 100% for all crude protein levels which floated for 60 minutes while the raw binder incorporated pellets performed poorly except for yam binder that gave 70% floatation rate at 40% crude protein levels. Thus, while considering the right polysacharides as binder for on-farm floating feed, Cassava binder is recommended.

CRUDE PROTEIN IN DIETS OF EUROPEAN QUAILS

Abstract The aim of this study was to evaluate crude protein (CP) levels for European quails from one to 14, 14 to 28 and 28 to 42 days old. The experiment was carried out in a completely randomized experimental design, with five treatments and five replications. No significant effects of CP levels on weight gain and feed conversion from 1 to 14 days were observed, however quails fed 26% CP diets had lower feed intake. The CP levels from 14 to 28 days had significant effect on feed intake, weight gain and feed conversion. Maximum weight gain and minimum feed conversion were estimated for quails fed 24% CP. The CP levels had a significant effect on the traits studied in the final phase, highest weight gain and lowest feed conversion were estimated for quails fed 23% CP. No significant effects of CP levels on hot and cold carcass weights, breast weight, and thigh and drumstick weight were observed. The crude protein requirements for European quails from 1 to 14, 14 to 28 days and 28 to 42 days old are 26, 24 and 23%, respectively, if the requirements of the first limiting amino acids are met.

Effects of crude protein levels on egg quality traits of brown layers raised in two production systems

The objective of this study was the evaluation of egg quality of 30 to 45-week-old brown layers, raised in cages or on floor, supplemented with amino acids, using the ideal protein concept with levels of 14, 15, 16, and 18% crude protein. A total of 400 birds (Hy-sex Brown) were used, distributed into two breeding systems (conventional cage or floor). The evaluated variables were the yolk relative weight, yolk height, albumen relative weight, albumen height, specific gravity, eggshell thickness, and eggshell weight. Treatments consisted of reduced levels of crude protein and were provided to both groups equally. We adopted a completely randomized design, in a factorial scheme, composed of two breeding systems and four levels of crude protein, totaling eight treatments. Five replicates per treatment and 10 birds per experimental unit were used. The breeding system on floor was configured as an option in the breeding of brown layers, of Hy-sex Brown commercial lineage, in the period between the 30th and the 45th week of age, since it presents results equivalent to the ones obtained in the breeding system in cages, having the egg quality as parameter. The system of production on floor is configured as an option in the farming of brown layers, of the commercial lineage Hy-sex Brown.

Effects of crude protein level and degradability of limited creep-feeding supplements on performance of beef cow-calf pairs grazing limpograss pastures

Two experiments evaluated the growth performance of cow-calf pairs offered limited creep-feeding supplementation (Exp. 1) and creep-feeding supplements with different crude protein degradability (Exp. 2). In Exps. 1 and 2, Brangus crossbred cow-calf pairs (Bos sp.; 24 and 16 pairs, respectively) were randomly assigned into 1 of 8 limpograss pastures (3 and 2 cow-calf pairs/pasture, respectively). Treatments were randomly assigned to pastures (4 pastures/treatment) and consisted of: (Exp. 1) no creep-feeding supplementation (Control) or daily limit creep-feeding supplementation (Creep; 0.40kg/d of soybean meal) for 84d; and (Exp. 2) daily limited creep-feeding supplementation of 0.40kg/d of soybean meal (SBM; 35% RUP) or 0.40kg/d of cooker-expeller processed SBM (SP; SoyPLUS, West Central, Ralston, IA; 60% RUP) for 112d. In both experiments, creep-feed supplements were provided daily at 0800h in cow-exclusion areas. Body weight of cows and calves were assessed monthly, following 16h of feed and water withdrawal, whereas cow BCS was determined at the start and end of the study. In both experiments, herbage mass (HM) and hand plucked forage samples for nutritive value analysis were obtained at 14-d intervals from May to August (Exp. 1) and May to September (Exp. 2). Effects of treatment and treatment×time (P≥0.16) were not detected for HM, herbage allowance, in vitro digestible organic matter, and crude protein in both experiments. In Exp. 1, limited creep-feeding supplementation increased calf overall average daily gain (ADG, P=0.0005), but not cow growth (P≥0.19). In Exp. 2, effects of protein degradability were not detected for calf and cow growth performance (P≥0.14). In summary, limit creep-feeding supplementation of 0.40kg/d of soybean meal for 83d addressed weather-induced calf nutritional deficiencies and increased calf growth grazing limpograss pastures, without affecting cow growth performance and forage responses. In addition, increasing supplemental RUP consumption from 67 to 115g/d was not sufficient to impact limpograss herbage mass, nutritional composition, and growth performance of cows and calves.

Effects of crude protein level in concentrate supplements on animal performance and nitrogen utilization of lactating dairy cows fed fresh-cut perennial grass.

Nitrogen pollution of air and ground water from grazing cattle is of increasing concern. Although several studies have investigated mitigation strategies for nitrogen output from dairy cows fed conserved forages and concentrates, similar research on fresh-cut grass in addition to production parameters is limited. The current study, using 3dietary treatments and incorporating 2 genotypes, was designed to evaluate the effects of concentrate crude protein (CP) levels on animal production and nitrogen utilization efficiency (NUE) in lactating dairy cows. Twelve multiparous cows (6 Holstein and 6 Holstein × Swedish Red) were used in a changeover study with three 25-d periods and 3 diet treatments. Low, medium and high CP concentrate [14.1, 16.1, and 18.1%, respectively, dry matter (DM) basis] diets were fed at 32.8% DM intake combined with good-quality zero-grazed perennial ryegrass (18.2% CP, DM basis). Each period consisted of an adaptation phase (18d) housed as a single group, a 1-d adaptation phase in individual stalls, and a 6-d measurement phase with feed intake and feces, urine, and milk output recorded. We observed no significant interaction between cow genotype and concentrate CP level on any animal performance or NUE parameter. Total DM intake, milk yield and composition, and NUE were not affected by dietary treatment. However, increasing concentrate CP level increased (1) N intake by 42g/d and excretion in urine and manure by 38 and 40g/d, respectively, and (2) the ratio of urine N over manure N. Feeding high CP rather than low CP concentrate increased milk urea N (MUN) content by 3.6mg/dL and total MUN output by 1.08g/d. Crossbred cows had lower grass DM intake, total DM intake, total N intake, and energy-corrected milk yield. However, cow genotype had no significant effect on NUE or MUN parameters. Equations have been developed to predict urine N excretion using MUN output as a sole predictor or in combination with dietary CP level. The present study indicated that when grazing cows are fed good-quality pasture, feeding concentrates with a protein content as low as 14.1% may not negatively affect productivity. In addition, reducing concentrate CP concentration may be successful in reducing the urinary N excretion of lactating dairy cattle on pasture-based systems, but further research is needed to investigate the long-term effects of supplementary concentrate CP content on milk production.

Does a reduction in dietary crude protein content affect performance, nutrient requirements, nitrogen losses, and methane emissions in finishing Nellore bulls?

An experiment was conducted to evaluate whether a reduction in dietary crude protein (CP) content affects animal performance, energy and protein requirements, N losses, and enteric methane emission in finishing Nellore bulls. Twenty-six animals, with an average age of 20±1.0months and initial body weight (BW) of 296±8.1kg were used in this experiment. Four animals were used as baseline reference animals and were slaughtered at the beginning of the experiment. Four animals were fed at maintenance level (MAIN), whereas 18 bulls were divided into 3 groups (n=6 in each group) and were randomly assigned to the treatments consisting of three levels of CP in the diets: 10, 12, and 14% of CP. At the end of the experiment, all animals were slaughtered to evaluate their chemical body composition, energy and protein requirements, and carcass characteristics. A linear effect was observed for dietary CP level on CP intake and digestibility, while greater values were obtained for animals that were fed 14% CP. Nitrogen metabolism was affected by CP levels, where animals that were fed 12 and 14% CP had greater urinary N losses than those that were fed 10% CP. There was no effect of CP level on retained N, animal performance, and carcass characteristics among diets, and there was no effect of CP level on microbial efficiency and CH4 emissions. Thus, this study showed that for finishing bulls, the level of dietary CP did not interfere with muscle deposition and greenhouse gas emissions. The reduction of CP content in diets does not affect DM intake, animal performance, and carcass characteristics, thereby suggesting that the use of 10% of CP in diets for finishing bulls reduces their environmental impact due to a lower urinary N excretion than 12 and 14% CP-based diets. Animals that were fed 10, 12, and 14% CP diets had emissions equivalent to 3893; 3755; and 4255gd−1 of CO2, respectively, and no difference was observed among diets. Furthermore, methane emission is not affected by CP levels ranging between 10 to 14% which, on average, is 16.3gkg−1 of DM intake. Our study found that a decreased CP level did not influence animal performance, but it did decrease N losses in manure without affecting methane emissions. However, it is important to highlight that more studies are necessary to confirm these results.

Effects of diets with high and low protein contents and two concentrate levels in Santa Ines×Texel lambs

Two experiments were conducted to evaluate the effects of diets containing two levels of crude protein (CP) and concentrates on the intake, total nutrient digestibility, nitrogen balance (NB), microbial efficiency, and performance of lambs. The diets consisted of 10% or 14.25% CP and 40% or 60% concentrate, with corn silage as the forage. In the digestibility assay, four intact male F1 Santa Ines×Texel lambs, with an average body weight of 21.0±2.48kg and rumen-cannulated, were used. The lambs were distributed in a 4×4 Latin square design with four treatments and four periods. There was no effect of the CP×concentrate interaction on the variables that were studied. There was an effect of CP levels on the intake and digestibility of CP, as well as on the amounts of N that were ingested, absorbed, and retained from urine (NB). There was also an effect of CP levels on uric acid excretion. In the performance assay, 32 intact F1 Santa Ines×Texel lambs with an average body weight of 19.0±2.02kg were used. They were distributed in a 2×2 factorial arrangement of treatments in a randomized block design with eight replicates. There was a significant interaction between CP and concentrate levels on the ether extract (EE) intake. The CP level affected the intake of dry matter (DM), organic matter (OM), CP, neutral detergent fiber corrected for ash and protein (apNDF), non-fiber carbohydrates (NFC), total digestible nutrients (TDN), and rumen-degraded protein (RDP), as well as the carcass gain (CG) and the feed conversion (FC). Concentrate levels affected the intake of DM, OM, CP, NFC, TDN, and RDP, as well as the CG, the CG/average daily gain (ADG), and the FC. It was concluded that levels of CP and concentrate do not affect microbial efficiency or nutrient digestibility, except for CP digestibility. A high level of CP or concentrate in the diet results in greater nutrient intake and better animal performance.

Effects of crude protein level in the concentrate and time allotment on pasture on milk yield, urinary nitrogen, and purine derivative excretion in lactating Latxa ewes

This study assessed the influence of reducing the crude protein (CP) content (from 190 to 130 g/kg CP/kg) in the supplementary concentrate and time allotment on pasture (TAP) on the milk yield, bodyweight, and the urinary nitrogen (N) and purine derivatives (PD) in lactating Latxa ewes. Animals were reared in a production system that restricted the amount of time that ewes spent on pasture. In mid-April, at the start of the 42 days experiment, 40 dairy Latxa ewes were assigned to one of four groups on the basis of their initial milk yield, days in lactation (DIL), bodyweight (BW), and condition score; thereafter, each group grazed in its own fenced paddock. The experiment was based on a 2 × 2 factorial design that included two CP levels and two pasture grazing regimes: 4 h continuous grazing (CG) in the morning or 2 h grazing in the morning and 2 h in the afternoon (DG). Individual milk yield was recorded three times a week, and time spent grazing and BW was recorded weekly. In the middle (day 15–17; P1) and at the end (day 36–38; P2) of the experiment, urinary spot samples were collected using a catheter. At the end of the experiment, ewes were confined to metabolic cages and urine was collected. CP level of the concentrate was not correlated with time spent grazing; however, the ewes that were permitted access to pasture twice per day spent more time grazing (223 min/day vs 207 min/day, P &lt; 0.01) and were more efficient with their time (56 min/h grazing vs 52 min/h, P &lt; 0.05) than the ewes that were permitted access to pasture once per day. Concentrate CP levels were not correlated with milk yield or composition, although ewes that received the high protein (HP) lost more weight than did those that received the low protein (LP) concentrate. Concentrate CP level and TAP were not correlated with creatinine (CR) excretion rate (mean = 315 µmol/kg LW0.75 s.e. 0.0161). Urea-N was the largest component of urinary-N (68.7 s.e. 2.33%; P &gt; 0.05), and urea-N waste was higher in HP ewes (202.7 mmol/day) than it was in LP ewes (159.5 mmol/day) (s.d. 27.83; P &lt; 0.01). Ewes subjected to the DG regime had significantly (P &lt; 0.01) higher urinary PD excretion (23.6 vs 21.4 mmol/day s.d. 4.01; P &lt; 0.01), and tended (P &lt; 0.1) to excrete less urea-N (175.1 vs 188.3 mmol, s.d. 27.83) than did the CG ewes. A reduction in the CP in the supplementary concentrate led to a reduction in N waste without having a detrimental effect on performance or milk production.

Intake, nutrient digestibility and milk yield of dairy cows fed urea and two levels of crude protein in diets with sugar cane.

The objective of this study was to evaluate the effect of two Crude Protein (CP) levels and two nitrogen sources in the diets of dairy cows on DM and nutrient intake, total apparent digestibility, ruminal fermentation, milk yield and composition and energy balance using sugarcane as forage. Twelve multiparous Holstein cows, averaging 235 days of milking and 22.0 kg of milk day were distributed into three balanced and contemporary 4x4 Latin squares. The study consisted of four experimental periods of 21 days with 14 days for diet adaptation and the remainder for sampling. The cows were fed isocaloric diets with ad libitum intake and forage based on sugarcane in a 2x2 factorial arrangement of treatments: two main nitrogen sources (soybean meal andurea) and two levels of CP and 156 g CP kg-1 DM). Milk samples for compositional analysis were collected on the 14-17th days of each period. Ruminal fluid samples were collected by an esophageal tube, 3 h after morning feeding, for pH, short chain fatty acid and ammonia nitrogen analysis. Apparent digestibility was determined by means of an internal indicator (ADFi). No effect of diet was observed on Dry Matter Intake (DMI) (kg/day), net energy for lactation (Mcal/day) or total nutrientapparent digestibility. Interactions between nitrogen source and diet crude protein content were observed on rumen pH (p = 0.007) and acetate to propionate ratio (p = 0.003). A tendency was observed (p = 0.052) toward an effect of CP levels on milk protein yield (kg/day) as the cows fed diets with soybean meal produced more milk protein than those fed diets with urea. The results indicate that diets with lower levels of CP do not alter the milk yield and composition of dairy cows in the final third of lactation.

Performance of Gestating Grasscutters (Thryonomys swinderianus) Fed Cassava-based Diets with Graded Protein Levels

Forages and crop residues are inexpensive and easily available feedstuffs for feeding grasscutters in captivity. These feedstuffs are nutritionally poor, not balanced for optimum performance and, therefore, required supplementation. Protein requirement of growing grasscutters was determined using thirty two 10-weeks old male grasscutters of equal weights. The grasscutters were separated into four groups and fed forage supplemented with concentrate diets, which differed in their protein contents of 8, 12, 16 and 20%, respectively but having the same energy level. Cassava root meal served as the main source of energy. The experiment, in a completely randomized design, lasted 10 weeks, during which feed intake and growth performance of the grasscutters were examined. Results showed that growing grasscutters were not significantly influenced by differences in the levels of crude protein in their diets. However, it appeared that grasscutters on the 12% crude protein diet ranked best in respect of feed intake and weight gain, while those on the 20% crude protein diet had the lowest feed intake and weight gain, but the best feed conversion ratio. The cost to gain ratio was significantly (P<0.05) influenced by the diets. Also, the cost effectiveness of diets increased with increase in dietary crude protein. It is, therefore, concluded that though the effect of crude protein levels on feed intake and weight gain were not significantly different, the higher ranking in respect of these parameters on the 12% crude protein diet suggests that the optimum crude protein requirement for growing grasscutters on cassava-based diets is 12%.

Modulation of glycogen and breast meat processing ability by nutrition in chickens: Effect of crude protein level in 2 chicken genotypes1

The aim of the study was to evaluate the impact of 2 isoenergetic growing diets with different CP (17 vs. 23%) on the performance and breast meat quality of 2 lines of chicken divergently selected for abdominal fatness [i.e., fat and lean (LL) lines]. Growth performance, breast and abdominal fat yields, breast meat quality parameters (pH, color, drip loss), and muscle glycogen storage at death were measured. Increased dietary CP resulted in increased BW, increased breast meat yield, and reduced abdominal fatness at slaughter regardless of genotype (P < 0.001). By contrast, dietary CP affected glycogen storage and the related meat quality parameters only in the LL chickens. Giving LL chickens the low-CP diet led to reduced concentration of muscle glycogen (P < 0.01), and as a result, breast meat with a higher (P < 0.001) ultimate pH, decreased (P < 0.001) lightness, and reduced (P < 0.001) drip loss during storage. The decreased muscle glycogen content observed in LL receiving the low-CP diet compared with the high-CP diet occurred concomitantly with greater phosphorylation amount for the α-catalytic subunit of adenosine monophosphate-activated protein kinase and glycogen synthase. This was consistent with the reduced muscle glycogen content observed in LL fed the low-CP diet because adenosine monophosphate-activated protein kinase inhibits glycogen synthesis through its action on glycogen synthase. Our results demonstrated that nutrition is an effective means of modulating breast meat properties in the chicken. The results also highlighted the need to take into account interaction with the genetic background of the animal to select nutritional strategies to improve meat quality traits in poultry.

The Effect of Crude Protein Level in Diets on Serum Biochemical Indexes and Intestinal Microflora of Yellow Quails

A study was carried out to determine the effect of crude protein level in diets on Serum Biochemical Indexes and Gastrointestinal Micro flora of yellow quails. Four diets with different crude protein levels 17.75%, 19.95%, 21.85%, 24.08% were used to feed 192 yellow quails during 50-day-old to 95-day-old in thi s experiment. The quails were randomly assigned to 4 groups by similar body weight, each of which was subdivided into 4 replicates of 12 quails each. At 95-day-old, two quails per replicates were selected randomly and slaughtered to collect the blood the caecal contents. The blood sample was used to analysis serum biochemical. The caecal contents was detected the colibacillus, lactobacillus and bifidobacterium. The results showed that ALT of diet 1 was significant low (p 0.05). Serum TP of treatment 3 is high than treatment 1 (p 0.05). The colibacillus and bifidobacterium were decreased and lactobacillus increased with the increased in dietary protein though there were no significant difference (p>0.05). These results indicated that the different level of dietary protein could not effect on gastrointestinal microflora significantly but significantly effect on serum biochemical indexes of yellow quails.

Effect of crude protein and phosphorus level on growth performance, bone mineralisation and phosphorus, calcium and nitrogen utilisation in grower-finisher pigs

Two experiments in a 2 × 2 factorial arrangement were conducted to evaluate the effect of crude protein (CP) (130 vs. 200 g/kg) and phosphorus (P) (4.0 vs. 6.0 g total P/kg) level in a phytase supplemented diet (500 FTU [phytase units]/kg) in grower-finisher pigs. Owing to the design of the experiment, as dietary P level increased, there was also an increase in dietary calcium (Ca) level in order to maintain a dietary Ca to P ratio of 1.6:1. In Experiment 1, four diets were fed to 56 pigs (n = 14, initial body weight [BW] 36.7 ± 4.2 kg) to investigate the interaction between CP and P on growth performance, bone mineralisation and digesta pH. Experiment 2 consisted of 16 entire male pigs (n = 4; offered identical diets to that offered in Experiment 1) for the determination of total tract apparent digestibility and nitrogen (N), P and Ca utilisation. There was an interaction between CP and P level on bone ash, bone P and bone Ca concentrations (p < 0.05). Pigs offered low CP–low P diets had a higher bone ash, P and Ca concentrations than pigs offered high CP–low P diets. However, there was no effect of CP level at high P levels on bone ash, P and Ca concentrations. Pigs offered low P diets had a lower ileal pH compared with pigs offered high P diets (p < 0.05). In conclusion, offering pigs a high CP–low P, phytase-supplemented diet resulted in a decrease in bone mineralisation.

The Effect of Crude Protein Level in Diets on Laying Performance, Nutrient Digestibility of Yellow Quails

Four diets with different crude protein levels 17.75%, 19.95%, 21.85%, 24.08% were used to feed 192 seven-week-old yellow quails in this experiment. During 50-day-old to 95-day-old, laying rate, feed intake and egg weight were recorded to analysis the effect of different levels of dietary protein on the performance of yellow quails. All fences were collected and analysis the effect of different levels of dietary protein on feed digestibility and Crude Protein utilizablity of yellow quails. The results showed that there was no significant difference of the average egg weight in four diets. The laying rate of diet 2 is significant high than others (p 0.05) but significant of EE and total organism and the utilizability of crude protein was significant difference (p<0.05) in four diets. Result showed that dietary crude protein had significant effect not only on laying performance but also on nutrient digestibility and 20% dietary crude protein was optimum for yellow-feather quails.