Different Levels Of Crude Protein Research Articles

IMPACT OF CONCENTRATES WITH VARYING LEVEL OF METABOLIZEABLE ENERGY AND CRUDE PROTEIN ON GROWTH RATE AND NUTRIENT DIGESTIBILITIY IN MALE BUFFALO GROWING CALVES

Twenty buffalo male calves of Nili Ravi breed with 10-12 months of age and 100+ 10 kg of weight were enrolled in this research to see the effect of different levels of crude protein (CP) and metabolizable energy (ME) on dry matter intake (DMI), growth rate and digestibility of nutrients in male buffalo calves. Four experimental rations A, B, C and D were prepared with two levels of CP i.e. 16.0 and 18.0% along with two varying levels of ME i.e. 2.82 & 2.94 Mcal/kg. The animals were individually fed with ad libitum feeding. Buffalo calves who had consumed B&D diets containing 2.94 Mcal/ had higher feed intake (DM basis) kilogram/day and weight gain but the difference was non significant statistically(P>0.05) among all the treatment groups. However, feed conversion efficiency was significantly different (P<0.05) among the treatments and was better in calves who had consumed diets A &C comprising 2.82 Mcal/kg).DMI digestibility were significantly (P<0.05) higher in the animals fed on diet having high levels of energy other than low energy level while digestibility of CP was significant (P<0.05) among the different groups however and NDF digestibility was almost same in all groups showing non significant difference (P<0.05).It was concluded that Nili Ravi male buffalo calves require more metabolizable energy than beef cattle as endorsed by NRC (2001).

Expression of enzymes involved in the urea cycle and muscle and mammary gland development of Holstein × Gyr heifers in a rotational grazing system supplemented with increasing protein levels

Studies evaluating the crude protein (CP) supplementation strategies across the year for grazing cattle and its association with the enzymes involved in the urea cycle and muscle and mammary gland developments are scarce. Thus, we aimed to evaluate the effect of supplementation with different levels of CP on the expression of genes involved in the urea cycle and muscle and mammary gland development of Holstein × Gyr crossbreed heifers grazing intensively managed Brachiaria decumbens throughout the year. Thirty-eight heifers with average initial BW of 172.5 ± 11.15 kg (mean ± SE) and 8.2 ± 0.54 mo of age were randomly assigned to 1 of 4 treatments: 3 protein supplements (SUP) fed at 5g/kg of body weight, plus a control group (CON, non-supplemented animals). The supplement CP levels evaluated were: 12, 24, and 36%. The study was divided into 4 seasons: rainy, dry, rainy-dry transition (RDT), and dry-rainy transition (DRT). On the penultimate day of each season, ultrasound images of the carcass and mammary gland were taken. Five animals from each treatment were randomly chosen on the last day of each season, and liver and muscle tissue biopsies were performed. The target genes were the mammalian target of rapamycin (mTOR) and adenosine monophosphate-activated protein kinase (AMPK) in the muscle samples. Carbamoyl phosphate synthetase (CPS), ornithine transcarbamylase (OTC), argininosuccinate synthetase (ASS), arginosuccinate lyase (ASL), and arginase (ARG) were evaluated in the liver samples. Data were analyzed using PROC GLIMMIX of the SAS with repeated measures. We observed a greater rib eye area (cm2) and fat thickness (mm) in SUP animals than in non-supplemented animals. However, we did not observe differences among SUP levels for both variables. No effects of supplementation were detected on mammary gland development. Nevertheless, seasonal effects were observed, where the RDT and dry season had the most and least accumulated fat in the mammary gland. In muscle, we observed greater expression of AMPK in non-supplemented animals than SUP animals. On the other hand, no differences were observed in gene expression between SUP and non-supplemented animals and among SUP animals for mTOR. Season affected both AMPK and mTOR; heifers had a greater AMPK gene expression on rainy than RDT. For mTOR, we observed greater gene expression in RDT and DRT than in rainy. No differences were observed among RDT, dry, and DRT, and between dry and rainy seasons for mTOR. We observed greater CPS, ASL, and ARG gene expression in SUP animals than in non-supplemented animals. Among SUP animals, supplement CP linearly affected CPS. In conclusion, the supplementation strategy did not affect mammary gland development and mTOR expression in muscle tissue. However, we observed a seasonal effect on mammary gland development and AMPK and mTOR expression. The CP supplementation increased the rib eye area and fat thickness, directly affecting AMPK expression in the muscle. Moreover, the CP supplementation increased urea cycle enzyme expression, indicating greater urea production in the liver.

Effect of reducing dietary crude protein level on growth performance, blood profiles, nutrient digestibility, carcass traits, and odor emissions in growing-finishing pigs.

This study was conducted to evaluate the effect of a low-protein (LP) diet on growth performance, carcass traits, nutrient digestibility, blood profiles, and odor emissions in growing-finishing pigs. A total of 126 crossbred pigs ([Yorkshire × Landrace] × Duroc) with an average body weight (BW) of 38.56 ± 0.53 kg were used for a 14-week feeding trial. Experimental pigs were allotted to one of 6 treatments in 3 replicates of 7 pigs per pen in a randomized complete block design. Pigs were fed each treatment diet with different levels of crude protein (CP). Phase 1 (early growing): 14%, 15%, 16%, 17%, 18%, 19%; phase 2 (late growing): 13%, 14%, 15%, 16%, 17%, 18%; phase 3 (early finishing): 12%, 13%, 14%, 15%, 16%, 17%; phase 4 (late finishing): 11%, 12%, 13%, 14%, 15%, 16%. All experimental diets in each phase were contained the same concentration of lysine (Lys), methionine (Met), threonine (Thr), and tryptophan (Trp). Over the entire experimental period, there was no significant difference in body weight (BW), average daily feed intake (ADFI), and gain-to-feed ratio (G:F ratio) among all treatments (p>0.05), but a quadratic effect (p = 0.04) was observed in average daily gain (ADG) during the late finishing phase with higher ADG in Group D. Blood urea nitrogen concentration linearly increased with an increase in dietary CP levels (p<0.01). Regarding nutrient digestibility, excreted nitrogen in urine and feces and nitrogen retention linearly increased as the CP level increased (p<0.01). A linear effect was observed with increasing CP levels in amines, ammonia, and hydrogen sulfide in odor emissions (p<0.01). No significant effects were observed in the measurements of carcass traits and meat characteristics (p>0.05). In phase feeding, reducing the CP level to 14% in early-growing pigs, 13% in late-growing pigs, 12% in early-finishing pigs, and 11% in late-finishing pigs is recommended.

Effect of Using Different Levels of Crude Protein and Adding some Amino Acids to the Diet on some Blood Biochemical, Histological and Nitrogen Excretion Characteristics of Laying Hens Lohmann Brown

This experiment was conducted at the poultry house of the Department of Animal Production - College of Agriculture - Tikrit University for the period between 13/2/2021 and 8/5/2021 and aimed to use different levels of crude protein and add some amino acids to the diet of laying hens of Lohmann Brown breed The experiment included 240 chickens at the age of (34) weeks and continued for three production periods, each 28 days long. The treatments were fed as follows: T1: the base diet without any addition (control treatment according to the breeding guide). the other five treatments T2, T3, T4, T5 and T6, the base diet reduced the level of crude protein by 0.5, 1, 1.5, 2, and 2.5, respectively, and supported it with amino acids (lysine, methionine, threonine) to be equal to what it is in the control diet. The results were a significant superiority of the control treatment compared to all treatments of the experiment except for the sixth treatment in total protein in the blood serum, as well as the control treatment was significantly superior to all other treatments of the experiment in the concentration of uric acid in the blood serum. The other experiment treatments, and there was no significant difference between the treatments in the depth of the crypts. As for the ratio between the depth of the crypts and the height of the villus, the fourth and fifth treatments increased significantly compared to the control treatment, and there was no significant difference between them and the rest of the experiment treatments, as well as a significant increase in nitrogen proposed for the sixth treatment. Compared with other experimental parameters.

Impact of Different Levels of Crude Protein on Production Performance and Meat Quality in Broiler Selected for Slow Growth

The production performance and meat quality of the slow-growing hybrid Hubbard JA757 were monitored under conditions of diets differentiated by crude protein content. A total of 1200 as-hatched day-old chickens were equally and randomly allotted into two treatments (T-1 and T-2), with six replicates provided for each treatment (100 chickens/replicate). T-1 chickens received standard diets (according to Hubbard Company recommendations), and those in T-2 were fed diets supplemented with crude protein (+0.5% CP in the growing phase and +1.0% CP in the finishing phase). At the end of the investigations (age 56 days), the T-2 chickens performed better than the T-1 chickens for growth traits (+2.72% body weight; +2.77% daily growth gain; −0.34% mortality; and −4.15% feed conversion ratio); for slaughtering (+0.66% dressed yield; +1.10% breast weight; and +1.25% thigh weight); and for quality meat (+0.55% dry matter in thigh muscles and +1.52% dry matter in breast muscles) (p &gt; 0.05). Statistically significant differences (p &lt; 0.05) occurred between treatments for body weight, daily weight gain, and feed conversion ratio due to the 0.5% CP feed supplementation during the 15–28 day age period, justifying the usefulness of the CP increasing throughout the grower diet only and not during the finishing period.

Effects of protease enzyme supplementation in weanling pigs' diet with different crude protein levels on growth performance and nutrient digestibility.

The purpose of this study is to determine the impact of different levels of crude protein (CP) diets supplemented with dietary protease on the growth performance and nutrient digestibility of the weanling pigs. In a 5-week study, 100 crossbred ([Landrace × Yorkshire] × Duroc) of weaner pigs that have an average initial body weight (BW) of 7.17±1.06 kg were assigned to one of four dietary treatments with 5 replications and 5 pigs (3 gilts and 2 castrated male pigs) per pen in a randomized complete block design. The dietary treatments were as follows: Phase 1: CON: basal diets (20.60% CP); low protein (LP): CON − 0.30% CP; PLP1: (CON − 0.30% CP) + 0.05% protease; PLP2: (CON − 0.50% CP) + 0.05% protease. Phase 2: CON: basal diets (18.88% CP); LP: CON − 0.30% CP; PLP1: (CON − 0.30% CP) + 0.05% protease; PLP2: (CON − 0.50% CP) + 0.05% protease. The addition of protease to low CP diets significantly increased the feed conversion ratio (FCR) (p = 0.039), BW (p = 0.046), average daily gain (ADG) (p = 0.049), and average daily feed intake (ADFI) tended to increase (p = 0.053) in the young pigs during phase 1. However, FCR tended to increase throughout the experiment but did not change during phase 2, whereas BW, ADG, and ADFI stayed unchanged throughout phase 2 and overall. There was no significant difference in dry matter, nitrogen (N), and gross energy of nutrient digestibility in all phases and overall in weaned pigs with low CP when protease was fed. In contrast, adding protease to the low CP diets increased the tendency of N digestibility (p = 0.059) during phase 1. It is concluded that dietary protease supplementation tended to increase N retention during the first phase of the weaning period, hence increasing piglet performance.

Feeds formulated with alternative ingredients for bullfrog tadpoles (Lithobates catesbeianus)

Several foods are available for the formulation of rations in Brazil; however, the effectiveness of a few of these foods has been evaluated in diets for bullfrog tadpoles (Lithobates catesbeianus). This study aimed to evaluate alternative foods (worm meal, peeled banana, peeled pumpkin, and peeled avocado) with different levels of crude protein and ether extract for the nutrition of bullfrog tadpoles to obtain the best animal performance and water quality. In a 60 days long experiment, a total of 480 bullfrog tadpoles (stage 25 of the Gosner table, 1960) with an average weight of 0.107 ± 0.004 g, were used. The experimental design was completely randomized (DIC) in a factorial scheme (2x2) with four treatments [rations with 320 g/kg crude protein (CP) and 90 g/kg ether extract (EE); 380 g/kg CP and 90 g/kg EE; T3:320 g/kg CP and 110 g/kg EE; 380 g/kg CP and 110 g/kg EE] each consisting of four replicates. To verify the normality of the data, the results of zootechnical performance, water quality, and proximate composition were subjected to the Shapiro-Wilk and Bartlett tests. Analysis of variance (ANOVA) was then performed, and the means were compared using Duncan's test at 5% of probability. The verified results of animal performance, water quality, and proximate composition were not influenced by the suggested diets. The best diet formulated based on easily acquired alternative ingredients can offer 320 g/kg CP and 90 g/kg EE to the tadpoles of bullfrog.

Effect of supplementation of acid protease in diets containing different levels of crude protein on performance of white leghorn layers

Effect of supplementation of acid protease in diets containing different levels of crude protein on performance of white leghorn layers

Pemberian Pakan Suplemen Selama Kebuntingan pada Induk Kambing Etawa

Nutritional improvement in goats can be done by regulating the provision of rations during goat mother's pregnancy in utero conditions that can affect fetal growth. Adequate supply of nutrients during goat mother's pregnancy is a major factor in the internal environment of the unborn child, which is expected to have an impact on better performance for the next life. In addition to being given a basal ration based on the treatment, the mother goats were given supplementary feed. Supplementary feed in the form of Urea molasses multinutrient block (UMMB) provided as much as 100-150 g/head/day. All pregnant goats were grouped according to gestational age and given supplementary feed according to the length of gestational age status. Supplementary feed given to pregnant goat contained different levels of crude protein (PK), 23.75%, 25.26% and 27.16%. Pregnant goat without supplementation of feed during pregnancy, goat mothers aged 1 to 2 months of pregnancy were given supplementary feed (first trimester). Parent aged 3 to 5 months of gestation were given supplementary feed (third trimester). pregnant goat mothers are given supplementary feed during pregnancy. The results of the study that different levels of protein supplement feed had an effect on dry matter consumption of the ration, the highest consumption was in the third trimester of pregnancy (gestational age of 3 to 5 months). Supplementary feeding during pregnancy resulted in high maternal weight gain. The level of digestibility of the feed in vivo, the highest crude protein digestibility level was in the supplementary feed containing 23.75% crude protein.

Supplementation of different zinc sources to low-CP diets and its effect on performance, carcass traits, liver and kidney functions, immunological, and antioxidant parameters of quail chicks

The present study was performed to evaluate the influence of low crude protein (CP) levels, zinc sources (organic as zinc methionine-Zn-Met and inorganic as zinc oxide-ZnO) and their interactions on growth performance, carcass traits, and blood components of growing Japanese quail. A total of 450 one-wk-old Japanese quail with the same body weights were randomly distributed into 9 groups of 50 birds. The 9-diet treatments comprised 3 levels of CP (20, 22, and 24%) and 3 Zn source (0 g of Zn/kg diet, 0.1 g ZnO/kg diet, and 0.1 g Zn-Met/kg diet). The results obtained from this study showed that there were no significant differences among the groups, except for differences in body weight (BW) and body weight gain (BWG) at 3 to 5 – and 1 to 5 wk of age for quail supplemented with 24% and 20% CP. All the studied biochemical parameters were significantly influenced by different levels of CP and Zn, except urea and creatinine, which were affected by CP levels only. In conclusion, dietary protein level for growing Japanese quails could be reduced to 20% without negative effects on their performance, carcass traits, and blood metabolites.

Decoupled FLOCponics systems as an alternative approach to reduce the protein level of tilapia juveniles' diet in integrated agri-aquaculture production

Decoupled FLOCponics (DFP) is a promising aquaponics approach which takes advantage of the nutritional benefits of biofloc technology (BFT). Enabling the use of less protein in the fish diets is one of the benefits of BFT. The effect of the reduction of protein content, and consequently the input of nitrogen, on fish and plant production in DFP systems has not yet been investigated. This study was designed to investigate and evaluate the production of lettuce and tilapia juveniles in a DFP system using different levels of crude protein (CP) in the fish diets. The zootechnical performance of tilapia juveniles and lettuce growth in the DFP system were evaluated, using different diets containing 24, 28, 32, and 36% CP. Fish production in DFP systems was compared to those reared in traditional decoupled aquaponics systems (DAPS) and in biofloc-based systems (BFT), both fed with 32% CP diet. The experimental period of tilapia juvenile production lasted 56 days. Lettuce production in two cycles was also performed in DFP systems with different CP levels and their growth was compared to those in DAPS and hydroponics systems, as control treatments. In Cycle 1, the seedling phase was evaluated in a 14-day trial. In Cycle 2, the final production phase was performed for 21 days until harvest. The physical-chemical parameters of the water were monitored in the aquaculture and hydroponic subsystems. High mortality of fish occurred in DFP-36 in the middle of the experiment, thus this treatment was discontinued. The results showed that tilapia reared in DFP and fed with 24 and 28% CP (DFP-24 and DFP-28) grew similarly to those in DAPS fed with 32% CP diet. Fish in DFP-32 and BFT fed with 32% CP diet grew similarly and above the other treatments. Additionally, plant growth results showed no differences in both cycles among all treatments. With respect to water parameters, even though more nutrients were inputted in the treatments with high CP content in the aquaculture subsystem, the mean values of nitrogen compounds and orthophosphate were similar in all treatments. For water parameters in the hydroponics subsystems, only the mean values of pH in Cycle 1 were statistically different in the plant treatments. The results obtained in this study indicate that using less CP in fish diets to produce lettuce and tilapia juveniles is technically possible and feasible in a decoupled FLOCponics system.

Biological efficiency of lipids in rainbown trout flesh depending on protein levels in feeds

The article considers the effect of using complete feeds with different protein levels on the biological efficiency of rainbow trout flesh lipids. The purpose of the experiment was to determine the effect of different levels of commercial rainbow trout’s protein nutrition on the fatty acid composition of flesh lipids and their biological effectiveness. For this purpose, five experimental groups were formed by the method of analogues. The experiment lasted 210 days and was divided into two periods: equalization (10 days) and basic (200 days). During the equalization period, the experimental fish consumed feed of the control group. In the main period, the level of protein in experimental feeds for different experimental groups of trout ranged from 44 to 52% per 1 kg. Rainbow trouts were fed 4–6 times a day during the experimental period, at regular intervals during the day. The required amount of feed was calculated according to the indices of individual fish weight and ambient temperature at the time of feeding. Commercial second-summer trouts were reared in ponds with an area of 100 m2 at the fish-holding density of 50 specimens/m2 and the water level of 1 m. The total number of trout in the experimental studies was 25 thousand specimens. It has been established that the consumption of compound feed with different levels of crude protein by second-year rainbow trout significantly affects the changes in the fatty acid composition of their flesh. As a result of the study it was found that the dominant fatty acids are oleic (C18: 1) - 14.44–18.92 % and palmitoleic (C16: 1) - 5.19–11.09 %. The increase in the level of crude protein in the feed of commercial rainbow trout to 52 % contributed to an increase in the content of saturated fatty acids in flesh by 7.9 % compared to the control. It has also been found that the use of compound feeds with a high level of protein nutrition lead to a decrease in the content of stearic acid in flesh. The results of experimental studies showed that among the polyunsaturated fatty acids in the lipids of rainbow trout’s flesh, the highest content beloned to linoleic fatty acid (C18: 2) – 1.76–2.2 %.

Effect of a Phytogenic Feed Additive on Growth Performance, Nutrient Digestion, and Immune Response in Broiler-Fed Diets with Two Different Levels of Crude Protein.

Simple SummaryThe rising concerns on antibiotics resistance from using antibiotics in animal production has resulted in an increase in researches on antibiotic alternatives. A phytogenic feed additive from a blend of extracts of oregano, cinnamon, citrus peel, and fructooligosaccharides was evaluated in the present study. The objective of the present study is not only to evaluate the effect of phytogenic feed additive on broiler performance, but also to explore the potential mode of actions through immune response, digestive enzyme activities, nutrient transporter gene expressions and nutrient digestibility. Supplementation of phytogenic feed additives improved broiler FCR through stimulating ileum immunity.The aim of this experiment was to evaluate the effect of a phytogenic feed additive (PFA) on growth performance and nutrient digestibility of broilers fed corn and soybean meal-based diets containing two different levels of crude protein. A 2 × 2 completely randomized factorial arrangement (eight replicates/treatment, 30 birds/replicate) was conducted with a positive control (PC) and negative control (NC) containing crude protein at standard or reduced by 1.5% (equivalent to a reduction of 15 g/kg), respectively, and supplementation of PFA at 0 or 125 ppm of diet. There were no significant interactions found between PFA and CP levels in the current study. Main effect analysis showed that during 0–42 d of age NC diets decreased body weight gain (p < 0.05), but increased feed intake (p < 0.05) and feed conversion ratio (FCR, p < 0.01), whereas supplementation of PFA resulted in a lower FCR (p < 0.01). The ileal nutrient digestibility was reduced (p < 0.05) in the broilers fed a reduced protein diet at 21 d compared to the standard protein level group, but there were no effects for PFA levels. Similarly, supplementing PFAs showed no effects on digestive enzyme (Alkaline phosphatase, amylase, and lipase) activity in jejunal digesta and jejunal brush border enzyme (maltase, sucrase, and aminopeptidase) activity. Supplementation of PFA downregulated (p < 0.05) the mRNA expressions of cytochrome P450 1A and interleukin 6 in the ileum but had no effects on nutrient transporter genes in the jejunum. In conclusion, supplementation of PFA reduced broiler FCR during the whole grow-out period and positively regulated the immune responses in the ileum.

Relationship between feed protein content and faeces nitrogen content in early lactation dairy cows

Relationship between feed protein content and faeces nitrogen content in early lactation dairy cows

Effects of different levels of crude protein and protease on nitrogen utilization, nutrient digestibility, and growth performance in growing pigs.

This study was conducted to evaluate the effects of different levels of crude protein (CP) and protease on nitrogen (N) utilization, nutrient digestibility, and growth performance in growing pigs. A total of six crossbred ([Landrace × Yorkshire] × Duroc) barrows were individually accepted in 1.2 m × 0.7 m × 0.96 m stainless steel metabolism cages. The pigs (average initial body weight of 27.91 ± 1.84 kg) randomly assigned to six diets with six weeks (6 × 6 Latin square design). The experiment was carried out in an environment with a temperature of 23 ± 1.5°C, a relative humidity of 83 ± 2.3% and a wind speed of 0.25 ± 0.03 m/s. The dietary treatments were arranged in a 2 × 3 factorial design with two levels of CP (15.3% or 17.1%) and three levels of protease (0 ppm, 150 ppm, or 300 ppm). The average daily gain and gain to feed ratio (G:F) tended to increase (p = 0.074) with increasing amounts of protease. The low CP level diet reduced (p < 0.050) urinary and fecal N concentrations, the total N excretion in feces, and increased (p < 0.050) N retention. Different protease levels in the diet did not affect (p > 0.05) at N intake, but supplementation of the diets with 300 ppm protease decreased (p < 0.050) the N concentration in urine and feces and tended to increase (p = 0.061) the percentage of N retention retained of the total N intake. The dietary CP level did not affect (p > 0.050) the apparent total tract digestibility (ATTD) of dry matter, digestible energy (DE), and metabolic energy (ME), but diet supplementation with 300 ppm protease showed higher (p < 0.050) ATTD of DE and ME than in the protease-free diet. Therefore, a low protein diet with protease could improve the utilization of nitrogen, thereby reducing the negative effect of N excretion into the environment while maintaining or increasing growth performance compared to a high protein diet.

Bacillus amyloliquefaciens CECT 5940 improves performance and gut function in broilers fed different levels of protein and/or under necrotic enteritis challenge

Two studies were conducted to investigate the effect of Bacillus amyloliquefaciens CECT 5940 (BA) as a probiotic on growth performance, amino acid digestibility and bacteria population in broiler chickens under a subclinical necrotic enteritis (NE) challenge and/or fed diets with different levels of crude protein (CP). Both studies consisted of a 2 × 2 factorial arrangement of treatments with 480 Ross 308 mix-sexed broiler chickens. In study 1, treatments included 1) NE challenge (+/−), and 2) BA (1.0 × 106 CFU/g of feed) supplementation (+/−). In study 2, all birds were under NE challenge, and treatments were 1) CP level (Standard/Reduced [2% less than standard]) and 2) BA (1.0 × 106 CFU/g of feed) supplementation (+/−). After inducing NE infection, blood samples were taken on d 16 for uric acid evaluation, and cecal samples were collected for bacterial enumeration. In both studies, ileal digesta was collected on d 35 for nutrient digestibility evaluation. In study 1, the NE challenge reduced body weight gain (BWG), supressed feed conversion ratio (FCR) and serum uric acid levels (P < 0.001). Supplementation of BA increased BWG (P < 0.001) and reduced FCR (P = 0.043) across dietary treatments, regardless of challenge. Bacillus (P = 0.030) and Ruminococcus (P = 0.029) genomic DNA copy numbers and concentration of butyrate (P = 0.017) were higher in birds fed the diets supplemented with BA. In study 2, reduced protein (RCP) diets decreased BWG (P = 0.010) and uric acid levels in serum (P < 0.001). Supplementation of BA improved BWG (P = 0.001) and FCR (P = 0.005) and increased Ruminococcus numbers (P = 0.018) and butyrate concentration (P = 0.033) in the ceca, regardless of dietary CP level. Further, addition of BA reduced Clostridium perfringens numbers only in birds fed with RCP diets (P = 0.039). At d 35, BA supplemented diets showed higher apparent ileal digestibility of cystine (P = 0.013), valine (P = 0.020), and lysine (P = 0.014). In conclusion, this study suggests positive effects of BA supplementation in broiler diets via modulating gut microflora and improving nutrient uptake.

Performance of brown layers fed reduced dietary protein levels in two rearing systems

ABSTRACT An experiment was conducted aiming to evaluate the effect of different levels of crude protein, based on the ideal protein concept and two rearing systems, on productive performance of brown laying hens. A total of 400 Hisex Brown laying hens between 30 and 45 weeks of age were distributed in a completely randomized design and a 2×4 factorial arrangement, with main effects including two rearing systems (cage and floor) and levels of crude protein (140, 150, 160, and 180 [...]

Interaction Between Crude Protein Level and Rumen Protected Amino Acids in Starter Diet on Performance of Dairy Calves

BACKGROUND: A limited number of studies have investigated the inclusion of amino acids in calf starter. OBJECTIVES: This study was aimed to evaluate different levels of crude protein in starter and supplement- ing some protected amino acids on efficiency, health status and blood metabolites of dairy calves and to com- pare it with unprotected amino acids. METHODS: Forty-eight 3-day-old Holstein calves were randomly allocated to four treatments in a complete- ly randomized design. Dietary treatments were (1) 18% Crude Protein starter without Amino Acid, (2) 18% Crude Protein with 0.0340% protected lysine and 0.016% protected methionine, (3) 18% Crude Protein starter with 0.215% un-protected lysine and 0.012% un-protected methionine, (4) 22% Crude Protein without Amino Acid. All calves received the same amount of whole milk, weaned on day 56; the study was finished on day 70. RESULTS: Calves in treatment 4 had the greatest starter intake, weaning weight and final weight (P 0.05). Health score (eye, ear, nose and respiratory score), was not different among treatments but the fecal score revealed a significant difference (P<0.05). Starter diet with 22% Crude Protein resulted in higher serum urea concentration (P< 0.05) CONCLUSIONS: Results of the present study indicate that, the performance of calves received protected or un-protected amino acid in starter was not different. Also, higher Crude Protein levels in diet did not lead to a better gain to feed ratio.

Environmental impacts of diets containing different levels of crude protein and limiting amino acids fed to pigs in a phase feeding system

Environmental impacts of diets containing different levels of crude protein and limiting amino acids fed to pigs in a phase feeding system

Effects of dietary protein levels on activities of protease and expression of ingestion and protein digestion‐related genes in Nile tilapia juveniles

While some studies have investigated the effects of dietary protein on the activities of protease in Nile tilapia, little information exists about these enzymes and hormones regulating appetite at the molecular level. Therefore, we investigated the performance, protease activities and expression of genes related to protein intake and digestion in juvenile tilapia fed with diets containing different levels of crude protein (CP): 25.14, 31.12, 36.60 and 42.05%. The fish were fed to apparent satiation three times a day for 65 days. The animal performance and the retention rates of protein and energy linearly decreased with an increase in dietary CP content. A positive quadratic effect of CP on pepsinogen was observed, although the acid protease activity was not affected. Trypsinogen and trypsin activity in the intestine presented similar patterns, showing a positive quadratic response to dietary protein levels. A linear increase in intestinal chymotrypsinogen expression was observed, but the activity of chymotrypsin showed a positive quadratic response. In addition, the expression of cholecystokinin (cck) and peptide yy (pyy) increased linearly with increasing CP. Dietary protein modulates the activity of alkaline proteases as well as the expression of these protease genes and hormones involved in appetite regulation. These changes can help expand our understanding of feed intake and digestion control, thereby improving feed formulations for this species.