Dietary Crude Protein Research Articles

Relationships between Dietary Chemical Components and Enteric Methane Production and Application to Diet Formulation in Beef Cattle

We used published data consisting of 263 treatment mean observations from beef cattle and dairy steers and heifers, in which CH4 was measured via chambers or head boxes, to evaluate relationships between enteric CH4 production and dry matter intake (DMI) and dietary components. Daily DMI was positively related (slope = 15.371, p < 0.001) to total daily production (g/d) of CH4 (r2 = 0.821). Among chemical components, dietary neutral detergent fiber (NDF) concentration was the most highly related (r2 = 0.696; slope = 0.2001; p < 0.001) to CH4 yield (g/kg of DMI), with strong relationships also noted for dietary starch:NDF ratio (r2 = 0.662; slope = −2.4587; p < 0.001), starch (r2 = 0.495; slope = −0.106; p < 0.001), and the proportion of metabolizable energy relative to gross energy (r2 = 0.561; slope = −23.663; p < 0.001). The slope (−0.5871) and intercept (22.2295) for the dietary ether extract vs. CH4 yield were significant (p < 0.001), but the relationship was highly variable (r2 = 0.150). For dietary crude protein concentration, the slope for CH4 yield was not significant (−0.0344; p < 0.381) with an r2 value near zero. Decreasing DMI by programming body weight gain or restricting feed intake could decrease CH4 production in confined cattle, but these approaches might negatively affect growth performance and product quality, potentially negating positive effects on CH4 production. Feeding higher-quality forages or using grazing management systems that decrease dietary NDF concentrations or substituting grain (starch) for forage should decrease both CH4 yield from enteric production and manure CH4 production via increased digestibility. Effects of feeding management and diet formulation strategies should be additive with other mitigation approaches such as feed additives, allowing the cattle industry to achieve maximal decreases in enteric CH4 production, while concurrently maintaining optimal beef production.

Effects of Varying Dietary Protein Levels on Growth Performance, Survival, Body Composition, Haemato-Biochemical Profile, and Metabolic Responses of Hypselobarbus jerdoni (Day, 1870) Juveniles

A 60-day feeding trial has been carried out to access the optimal dietary crude protein (DCP) requirement of juvenile Jerdon’s carp, Hypselobarbus jerdoni. Six isoenergetic (around 400 Kcal DE/100 g), isolipidic (60.80 g/kg), and heteronitrogenous diets were prepared with graded levels of protein, viz., 200, 250, 300, 350, 400, and 450 g/kg (TCP 20-TCP 45 with 50 g/kg incremental level). A completely randomised design (CRD) was used to distribute 270 Jerdon’s carp juveniles (6.12–6.18 g) in six experimental groups in triplicates (15 fish/tank, 200 l water capacity). After 60 days, the fishes of the TCP30 group showed significantly higher weight gain, final body weight, and percentage weight gain (WG%). The fish of the TCP30 group exhibited a significantly higher feed efficiency ratio and specific growth rate. On the other hand, a significantly lower feed conversion ratio is recorded in the TCP30 and TCP35 groups. The protein efficiency ratio of fish was reduced significantly with the elevated DCP level. Whole-body moisture, lipid, and total ash contents of H. jerdoni were remain unaffected by DCP levels. However, DCP levels significantly influenced the whole-body protein of H. jerdoni juveniles, with significantly higher values noticed in the TCP30 and TCP35 groups. The TCP35, TCP40, and TCP45 groups exhibited significantly higher (p<0.05) protease activity, and the amylase activity showed a decreasing trend in response to dietary protein levels. A significantly (p<0.05) higher SOD and CAT activity were observed in the TCP20 and TCP25 groups. However, lower hepatic glutamate pyruvate transaminase and glutamic-oxaloacetic transaminase activity were observed in the TCP30 and TCP35 groups, respectively. Furthermore, based on broken-line linear and second-order polynomial regression with respect to WG%, the optimal dietary crude protein requirement of H. jerdoni cultured for 60 days was found to be 309.72 and 316.40 g/kg.

Effects of dietary protein level on intestinal function and inflammation in nursery pigs.

High crude protein (CP; 21% to 26%) diets fed during the first 21 to 28 d postweaning are viewed negatively because of a perceived increase in the incidence rates of diarrhea due to increased intestinal protein fermentation and/or augmented enteric pathogen burden. This is thought to antagonize nursery pig health and growth performance. Therefore, our objective was to evaluate the impact of low vs. high dietary CP on 21-day postweaned pig intestinal function. Analyzed parameters included ex vivo intestinal barrier integrity (ileum and colon), ileal nutrient transport, tissue inflammation, and fecal DM. One hundred and twenty gilts and barrows (average body weight) were randomly assigned to one of two diets postweaning. Diets were fed for 21 d, in two phases. Phase 1 diets: low CP (17%) with a 1.4% standardized ileal digestible (SID) Lys (LCP), or high CP (24%) with a 1.4% SID Lysine (HCP). Phase 2: LCP (17%) and a 1.35% SID lysine, or HCP (24%) formulated to a 1.35% SID lysine. Pig growth rates, feed intakes, and fecal consistency did not differ (P > 0.05) due to dietary treatment. Six animals per treatment were euthanized for additional analyses. There were no differences in colonic epithelial barrier function as measured by transepithelial electrical resistance (TER) and fluorescein isothiocyanate (FITC)-dextran transport between treatments (P > 0.05). Interleukins (IL)-1α, IL-1β, IL-1ra, IL-2 IL-4, IL-6, and IL-12 were not different between treatments (P > 0.05). However, IL-8 and IL-18 were higher in HCP- vs. LCP-fed pigs (P < 0.05). There were no differences in fecal dry matter (DM; P > 0.05) between treatments. In the ileum, there was a tendency (P = 0.06) for TER to be higher in HCP-fed pigs, suggesting a more robust barrier. Interestingly, glucose and glutamine transport were decreased in HCP- vs. LCP-fed pigs (P < 0.05). FITC-dextran transport was not different between treatments (P > 0.05). There were also no differences in ileal cytokine concentrations between diets (P > 0.05). Taken together, the data show that low CP does not negatively impact colonic barrier function, fecal DM, or inflammation. In contrast, ileal barrier function and nutrient transport were altered, suggesting a regional effect of diet on overall intestinal function.

Whole-body urea kinetics and functional roles of urea transporters and aquaporins in urea secretion into the rumen in sheep fed diets varying in crude protein content and corn grain processing method.

The objectives were to determine the effects of dietary crude protein (CP) content and corn grain processing on whole-body urea kinetics and the functional roles of urea transporter-B (UT-B) and aquaporins (AQP) in serosal-to-mucosal urea flux (Jsm-urea) in ovine ruminal epithelia. Thirty-two Rideau-Arcott ram lambs were blocked by bodyweight into groups of 4 and then randomly allocated within blocks to 1 of 4 diets (n = 8) in a 2 × 2 factorial design. Dietary factors were CP content (11% [LP] vs. 16% [HP]) and corn grain processing (whole-shelled [WSC] vs. steam-flaked [SFC] corn). Whole-body urea kinetics and N balance were determined using 4-d continuous intrajugular infusions of [15N15N]-urea with concurrent collections of urine and feces with four blocks of lambs (n = 4). After 23 d on diets, lambs were killed to collect ruminal epithelia for mounting in Ussing chambers to determine Jsm-urea and the measurement of mRNA abundance of UT-B and AQP. Serosal and mucosal additions of phloretin and NiCl2 were used to inhibit UT-B- and AQP-mediated urea transport, respectively. Lambs fed HP had a greater (P < 0.01) N intake (29.4 vs. 19.1g/d) than those fed LP; however, retained N (g/d or % of N intake) was not different. As a % of N intake, lambs fed SFC tended (P = 0.09) to have a lower N excretion (72.2 vs. 83.5%) and a greater N retention (27.8 vs. 16.6%) compared to those fed WSC. Endogenous urea-N production (UER) was greater in lambs fed HP compared to those fed LP (29.9 vs. 20.6g/d; P = 0.02), whereas urea-N secreted into the gut (GER; g/d) and urea-N used for anabolic purposes (UUA; g/d) were similar. Lambs fed LP tended (P = 0.05) to have greater GER:UER (0.78 vs. 0.66) and UUA:GER (0.23 vs. 0.13) ratios, and a greater Jsm-urea (144.7 vs. 116.1 nmol/[cm2 × h]; P = 0.07) compared to those fed HP. Lambs fed SFC tended to have a lower NiCl2-insensitive Jsm-urea (117.4 vs. 178.4 nmol/[cm2 × h]; P = 0.09) and had a lower phloretin-insensitive Jsm-urea (87.1 vs. 143.1 nmol/[cm2 × h]; P = 0.02) compared to those fed WSC. The mRNA abundance of UT-B (0.89 vs. 1.07; P = 0.08) and AQP-3 (0.90 vs. 1.05; P = 0.07) tended to be lower in lambs fed SFC compared to those fed WSC. Overall, reducing CP content tended to increase the GER:UER ratio with no changes in the expression or function of UT-B and AQP. Although corn grain processing had no effects on GER, feeding SFC increased the portion of urea secretion into the rumen that was mediated via UT-B and AQP.

Growth performance and nitrogen excretion of broiler chickens fed low protein diets supplemented with crystalline amino acids.

This study was conducted to determine the effects of amino acid (AA) supplementation in low-protein (LP) diets on growth performance and nitrogen (N) excretion. A total of 175 7-day-old Ross 308 male broilers, with a mean body weight (BW) of 165 g (standard deviation = 11.2 g), were grouped into five blocks by BW and allocated to seven treatments according to a randomized complete block design with five replicate cages at five birds per cage. Dietary treatments comprised a control diet containing 20.0% crude protein (CP) and six LP diets containing either 18.5% or 17.0% CP. These LP diets were supplemented with either no AA supplementation, indispensable AA, or both indispensable and dispensable AA (glutamic acid and glycine). Birds were fed experimental grower diets from day 7 to 21 and then commercial finisher diets until day 28. During the grower period (day 7 to 21), birds fed LP diets supplemented with indispensable AA exhibited greater (p < 0.05) BW, body weight gain (BWG), feed intake (FI), and gain-to-feed ratio (G:F) than birds fed LP diets without crystalline AA and were comparable to birds fed the control diet. During the finisher period (day 21 to 28), birds fed LP diets supplemented with indispensable AA showed greater (p < 0.05) BW than birds fed LP diets without crystalline AA, and their growth performance was comparable to birds fed the control diet. Throughout the overall period, supplementing indispensable AA in LP diets resulted in elevated (p < 0.05) BWG, FI, and G:F more than those of LP diets without crystalline AA and were comparable to those of the control diet. Supplementing indispensable AA in LP diets decreased amount and coefficient of N excretion as much as the control diet. Dispensable AA supplementation in LP diets did not influence growth performance and N excretion. In conclusion, supplementing indispensable AA in LP diets maintains growth performance and N excretion until the dietary CP lowers from 20.0% to 17.0% during the grower period. As long as dietary CP is above 17.0%, dispensable AA may not be deficient in LP diets during the grower period.

The effect of protein and selenium on broiler performance and blood parameters in summer conditions

Heat stress presents a substantial challenge for the poultry industry, negatively impacting broilers' health, growth, and productivity. Optimizing dietary crude protein (CP) levels is a viable approach to reduce the heat generated during birds' amino acid oxidation process. Additionally, supplementing diets with Selenium (Se), a potent antioxidant, can help counteract the detrimental effects of heat stress on broiler growth performance. To explore the effects of varying CP and Se levels on growth performance, carcass characteristics, blood parameters, immune function, and blood leukocyte profiles in broiler chickens under heat stress, a 42-day experiment was conducted. It involved 528 male broiler chicks (Ross 308), divided into six groups with 11 chicks each, fed diets with 100%, 94%, or 88% of the recommended CP levels, and two Se levels (0 and 0.04 mg/kg). The findings indicated that reducing dietary CP levels led to an improvement in daily weight gain (DWG) without affecting feed intake (FI), feed conversion ratio (FCR), or carcass traits. There was a significant interaction between CP and Se levels regarding glucose, albumin, uric acid, cholesterol, triglyceride levels, antibody titers against Newcastle disease virus (NDV), and monocyte counts. Se supplementation increased NDV antibody titers at 14 days, whereas reducing CP lowered these titers at 21 days. The study concluded that lowering dietary CP did not adversely affect growth performance, carcass quality, or blood parameters; it even enhanced DWG compared to a normal protein diet and influenced some blood parameters.

Effect of Dietary Energy Level on Some Reproductive Characteristics of Clarias jaensis Female (Boulenger, 1909), an Endogenous Species from Cameroon

To determine the level of food energy necessary for a good sexual maturation of Clarias jaensis females in captivity, 180 post fingerlings with average weight of 96 ± 7g were submitted in triplicates to four experimental isoproteic (40 % crude protein) diet with 3000, 3100, 3200 and 3300 Kcal/kg of energy. The study took place at the Application and Research Farm of the University of Dschang for 4 months. At the end of the test, 12 females presenting the sexual maturity characteristics (bloated belly containing mature oocytes) from each group were sacrificed. The results showed that FSH (0.81 ± 0.35 mlU/ml) and LH (0.66 ± 0.23 mlU/ml) were higher at 3100 Kcal/kg while the higher concentration of estradiol (450,00 ± 109,86 pg/ml), the higher weight of ovaries (31,88 ± 6,86g) and the higher rate of mature female (75%) were recorded with 3000 Kcal/kg. Other reproductive characteristics such as ovarian biochemical characteristics, GSI, HSI and oocyte characteristics were also better with lower energy diets. In conclusion, females with the best reproductive characteristics were obtained with low energy rations.

Effects of Dietary Crude Protein Levels on Crossbred Buck Rabbit Semen Characteristics and Reproductive Performance of Does

Effects of Dietary Crude Protein Levels on Crossbred Buck Rabbit Semen Characteristics and Reproductive Performance of Does

Determination of Optimum Dietary Crude Protein Requirement for Maximum Growth of African Catfish (Clarias gariepinus)

Determination of Optimum Dietary Crude Protein Requirement for Maximum Growth of African Catfish (Clarias gariepinus)

Use of wheat dilution to improve digestive function in broilers: application in low protein diets

ABSTRACT 1. This study evaluated the effect of wheat dilution increasing in particle size in low crude protein diets on growth performance, digestive tract, nitrogen efficiency and litter quality in broiler chickens. 2. Ross 308 male broiler chicks (n = 336) were allocated to one of four dietary treatments (each with 7 pens, 12 chicks per pen); Control (CON; commercial pellet diet with standard crude protein, CP: 22.50%), W578 (CON +20% wheat of geometric mean diameter (GMD) of 578 µm; CP: 20.25%), W1326 (CON +20% wheat of GMD 1326 µm; CP: 20.25%) and WW (CON +20% whole wheat, CP: 20.25%), from d 0 to 21 of age. 3. Body weight gain was increased (P < 0.05) for birds fed CON compared to the low crude protein diets. However, WW increased (P < 0.05) body weight gain compared to W578 and W1326, while feed intake and feed conversion ratio on CON and WW were similar (P > 0.05). Birds fed W1326 showed the poorest (P < 0.05) FCR compared to CON, W578 and WW. 4. Gizzard relative weight (g/kg body weight) was increased (P < 0.05) on WW compared to CON on d 14 and 21, whereas gastric isthmus diameter was significantly reduced on W1326 and WW compared with CON and W578. 5. There were no differences (P > 0.05) in the depth of gizzard mucosa of lamina propria between CON and WW at d 14 and 21. Birds fed WW increased (P < 0.05) gizzard tensile strength compared to W578 and W1326, whereas no difference was observed between WW and CON on d 14. 6. No significant differences were seen for ileum villus height and mucosal layer between CON and WW on d 21, however, feeding CON increased the extent of the mucosal layer compared to W578 and W1326. 7. Nitrogen excretion (g/kg BWG) was significantly lower (P > 0.05) on W1326 and WW compared with CON and W578. Litter nitrogen, moisture, and footpad scores significantly decreased (P < 0.05) for birds fed WW compared with CON. 8. Diluting dietary protein content from 22.50 to 20.25% resulted in lower body weight gain in broilers. However, dilution with whole wheat resulted in comparable FCR, reduced nitrogen excretion, litter moisture and footpad dermatitis compared with a standard protein diet.

Crude protein requirements of light-weight feedlot steersduring a 35-d receiving period

The influence of dietary crude protein (CP) levels on growth performance, morbidity, and estimated dietary net energy (NE) of light-weight crossbreed feedlot calves during a 35-d receiving period was evaluated. For the above, 108 crossbred steers (196±13 kg) were used in 35-d receiving trial. Steers were randomly allocated to 18 pens (6 steers/pen, 6 replicas/treatment). Treatments consisted of a steam flaked corn-based receiving diet (72:28 concentrate to forage ratio) containing 12.5, 13.5 and 14.5% CP. Crude protein level in diet was manipulated by replacing steam flaked corn by canola meal. Steers were allowed ad lib. access to their experimental diets. Morbidity averaged 32%, and was not affected by treatments. Increasing the level of dietary CP improved average daily weight gain, gain efficiency and tended to increase the ratio of observed-to expected dietary NE. Furthermore, in CP range from 12.5 to 13.5%, these effects were evident, but were not apparent at 13.5 to 14.5% CP. It can be concluded that high-energy receiving diet formulations containing 13.5 to 14.5% CP will optimise initial growth performance of light-weight (~200 kg BW) feedlot calves. However, present effect may be more a function of achieving metabolisable amino acid rather than metabolisable protein requirements.

Growth performance, serum parameters, inflammatory responses, intestinal morphology and microbiota of weaned piglets fed 18% crude protein diets with different ratios of standardized ileal digestible isoleucine to lysine

The present study was to explore the Ile requirement of piglets fed 18% crude protein (CP) diets. Two hundred and fifty 28-day-old Duroc × Landrace × Yorkshire piglets (8.37 ± 1.92 kg) were randomly divided into 5 dietary treatments (10 piglets per replicate, 5 barrows and 5 gilts per replicate) with 45%, 50%, 55%, 60%, 65% standardized ileal digestible (SID) Ile-to-Lys ratios, and the SID Lys was formulated to 1.19%. The experimental design consisted of two phases (d 1 to 14 and d 15 to 28). Results showed that average daily gain (ADG) had a tendency to quadratically increase as the SID Ile-to-Lys ratio increased (P = 0.09), and the optimum SID Ile-to-Lys ratios required to maximize ADG were 48.33% and 54.63% for broken-line linear model and quadratic polynomial model, respectively. Different SID Ile-to-Lys ratios had no significant effects on average daily feed intake and gain-to-feed ratio. Dry matter (P < 0.01), CP (P = 0.01), ether extract (P = 0.04), gross energy (P < 0.01) and organic matter (P < 0.01) digestibility increased quadratically. Serum total cholesterol levels decreased linearly (P = 0.01) and quadratically (P < 0.01); aspartate aminotransferase (P < 0.01), interleukin-1β (P = 0.01), and tumor necrosis factor-α (P < 0.01) levels decreased quadratically; immunoglobulin G (P = 0.03) and immunoglobulin M (P = 0.01) concentrations increased quadratically. Serum Ser levels decreased linearly (P < 0.01) and quadratically (P = 0.01); Glu (P = 0.02), Arg (P = 0.05), and Thr (P = 0.03) levels decreased quadratically; Gly (P < 0.01) and Leu (P = 0.01) levels decreased linearly; Ile (P < 0.01) concentration increased linearly. Duodenal villus height (P < 0.01) and villus height to crypt depth ratio (P < 0.01) increased quadratically. The deficiency or excess of Ile decreased short chain fatty acid-producing bacteria abundance and increased pathogenic bacteria abundance. Overall, taking ADG as the effect index, the optimum SID Ile-to-Lys ratios of piglets offered 18% CP diets were 48.33% and 54.63% based on two different statistical models, respectively, and the deficiency or excess of lle negatively affected piglet growth rates and health status.

Effect of dietary concentrations of Metabolisable energy and crude protein on the performance and behavior of ducks

ABSTRACT 1. The study evaluated the effect of dietary metabolisable energy (ME) content and crude protein (CP) level on the growth performance and behaviour of ducks. 2. A total of 720, Cherry Valley ducks were allocated to 36 pens in groups of 20 birds. For the initial period, from 1 to 21 d age, six diets, containing a standard (SME), low (LME) and high (HME) ME of 12.14, 11.93 and 12.35 MJ/kg, and standard (SCP) or high (HCP) CP contents of 210 or 220 g/kg diet, respectively, were mixed. For the period from 22 to 42 d age, the diets contained ME of 12.98 (SME), 12.77 (LME), 13.19 (HME) MJ/kg and the levels of CP were 170 (SCP) or 180 (HCP) g/kg, respectively. 3. An ME by CP interaction was seen from 1 to 21 d age in ducks fed HME + HCP diet, which had greater weight gain than those fed LME + SCP (P < 0.05). Compared to LME + SCP, dietary HME decrease feeding but increased walking behaviour compared to LME + SCP and SME + SCP (P < 0.05). High CP in LME and SME diets increased drinking behaviour (P < 0.05), but there was no change in HME diet. Compared to LME, feeding HME reduced ground pecking (P < 0.05). Feeding HME reduced feeding behaviour (P < 0.05) from 22 to 42 d age. During the same period, standing behaviour was reduced in HCP + LME (P < 0.05). Drinking was reduced in LME + SCP compared to SME + HCP and HME + HCP (P < 0.05). 4. A diet formulated with HME and HCP is effective for enhancing growth performance of ducks aged 1-21 d and saving time for feeding or ground pecking, which may induce spending more time on other activities.

Dietary crude protein time-dependently modulates the bacterial community and metabolites and changes dietary nutrient efficiency in growing pigs

The reduced nutrient digestibility of low-protein (LP) diets has been shown to be caused by the weakened fermentative capacity of the post-gut flora. The dynamic regulation of dietary protein contents on post-gut microbial population and fermentative metabolism is unclear. Twelve growing barrows (19.9 ± 0.8 kg) fitted with a T-cannula at the blind end of the cecum were randomly administered a high-protein (HP, 21.5% crude protein [CP]) diet or an LP (15.5% CP) diet for 28 d. The cecal content and feces were collected at d 1, 14, and 28 of the experiment for microflora structures and metabolite concentrations analysis. The nutrient digestibility coefficient and plasma biochemical parameters were also determined. Compared with the HP treatment, the LP treatment showed decreased plasma urea nitrogen concentration and apparent total tract digestibility of dry matter, gross energy, and CP (P < 0.01). In addition, urinary nitrogen losses, total nitrogen losses, and daily nitrogen retention in the LP treatment were lower than those in the HP treatment (P < 0.01), and the nitrogen retention-to-nitrogen intake ratio in the LP treatment was increased (P < 0.01). The HP group showed increased cecal total short-chain fatty acids (SCFA) concentration and fecal propionate, butyrate, and total SCFA concentrations (P < 0.05) on d 14 and 28, which may be mainly related to the elevated abundance of SCFA-producing bacteria, such as Ruminococcus, Lactobacillus, and Prevotella (P < 0.05). Probiotics, such as Bifidobacterium, Bacteroidales S24-7, and Rikenella, enriched in the LP treatment possibly contributed to reduced plasma endotoxin content. The differences in the abundances of almost all the above-mentioned flora appeared on d 28 but not d 14. Likewise, differences in the Simpson and Shannon indices and clustering patterns of the microbiota between treatments were also only observed on d 28. To sum up, in a time-dependent manner, the LP diet increased probiotics with gut-improving functions and decreased SCFA-producing bacteria, which may cause enhanced intestine health and reduced nutrient digestibility.

Effect of Protein Concentrate Withdrawal and Reducing the Crude Protein in Diets and Supporting Them with a Mixtures of Essential Amino Acids on some Physiological Traits of Laying Hens

The study was conducted to show Effect of protein concentrate Withdrawal and reducing the crude Protein in diets and supporting them with a mixtures of essential amino acids on some physiological traits of laying hens. (128) laying hens, type Lohmann Brown, at the age of (21) weeks, was randomly distributed among 8 treatments, with 8 replications for each treatment, as each replication was carried out on (2) hen (16 chickens/treatment), And the experimental treatments were as follows: T1 control (standard diet) and T2 (a treatment devoid of protein concentration ), and treatments T3, T4, and T5 (in which the percentage of crude protein was reduced by 1% and add on a mixture of amino acids consisting of methionine, lysine, and threonine was added by 1, 1.5, and 2%, respectively), and treatments T6, T7, and T8 (in which the percentage of crude protein was reduced by 2%, and add on a mixture of amino acids consisting of methionine, lysine, and threonine was added by 1, 1.5, and 2%, respectively). The results showed that there were no significant differences between the treatments of the experiment, but it was noted that there was a significant superiority (P < 0.05) for the treatments of adding the mixture of amino acids in favor of the treatments T1 and T10 in terms of cholesterol, total protein and albumin, compared with the treatment of T1 and T2 control, as well as treatment recorded T1, T2 and T3 Highly significant (P<0.01) superiority in IgM and IgA traits. It can be concluded from this study that adding the mixture of amino acids by 1.5 and 2% and reducing the protein percentage by (1 and 2%) led to a significant improvement in some physiological characteristics compared with the control treatment

Salinity tolerance of Nile tilapia (Oreochromis niloticus) to seawater and growth responses to different feeds and culture systems

The inability to acclimatise, feed and grow Nile tilapia (Oreochromis niloticus) in full seawater salinity has been a major obstacle to farming in marine waters. We investigated the salinity tolerance of O. niloticus and growth responses to different feeds and culture systems. Fish were first acclimatised to different salinities in laboratory aquaria, and the survival and growth performance in sea water were then assessed in aquaria, cages and ponds. Acclimatization to seawater salinity (5 – 30) took place at a rate of 5 every 9 days. Fish were stocked at densities of 5 fish/20 L in aquaria, 5 fish/m2 in cages and 3 fish/m2 in ponds. Replicates of 5, 3 and 3 were performed in aquaria, cages and ponds, respectively. Fish were fed on commercial (1 and 2) and locally formulated (30 % crude protein) diets. Mortality rates were higher in aquaria, when fish were introduced to salinities between 5 and 30 over 24 hours. Gradual salinity adjustments attained a stable survival rate of 78 % at salinities above 30. Aquarium experiments indicated significant negative correlation between salinity and survival (p &lt; 0.001, r = 0.387) and daily growth rates varied with diet (0.01 – 0.05 g/day). Acclimatized fish showed minimal mortality in ponds and cages. Daily growth rates varied with diet and culture system; 0.54 - 2.48 g/day in cages and 1.1 - 2.5 g/day in ponds. Fish fed on commercial feed 2 showed significant growth rates for all culture methods (p &lt; 0.05). O. niloticus could be fully acclimatised to seawater and attained promising growth rates when subjected to different commercial diets indicating potential of farming the species in marine waters.

Utilization of Black Soldier Fly (Hermetia illucens) Larvae as a Potential Substitute for Fish Meal in the Production of Nile Tilapia (Oreochromis niloticus L.)

Utilization of quality aqua-feed relies heavily on fish meal sources of protein because of its nutritional balance. However, due to its limited supply, high cost, and decline of wild fish populations, aquaculture production has shifted focus to cheaper and more readily available alternatives to guarantee sustainable aquaculture productivity. Black soldier fly (Hermetia illucens) larvae are a promising replacement for fish meal in fish diets due to their relatively high crude protein, lipid and mineral contents, and the bioactive potential with anti-microbial, and other probiotic properties. This study determined the effect of partially replacing fish meal with black soldier fly meal (BSFLM) on the growth performance of Nile tilapia (Oreochromis niloticus). Four isonitrogenous (30% crude protein) diets in which fish meal protein was gradually substituted with BSFLM were prepared as follows: No BSFLM (control)-T0; 25% (BSFLM25)-T25, 50% (BSFLM50)-T50 and 75% (BSFLM75)-T75. The feeds were fed to the Nile tilapia fingerlings (mean weight 25 &amp;plusmn;5 g) which were randomly stocked in 12 cages at a stocking density of 30 fish per cage. The experimental fish were manually fed at 3% of the body weight for 28 days, and 4% of the body weight for 154 days twice a day. The study found that 25% and 50% replacement of fish meal protein with BSFLM resulted in the best growth performance of Nile tilapia, as measured by final mean body weight gain (BWG), specific growth rate (SGR), feed conversion ratio (FCR) and condition factor (K). This suggests that BSFLM is a promising alternative to fish meal in aqua-feeds in the production of Nile tilapia.

Enzymolytic soybean meal improves growth performance, economic efficiency and organ development associated with cecal fermentation and microbiota in broilers offered low crude protein diets.

The objective of this experiment was to determine the effect of low crude protein (CP) diets containing increasing amounts of enzymolytic soybean meal (ESBM) on growth performance, economic benefit and organ development and the role of cecal fermentation and microbiota in broilers. A total of 360 one-day-old Arbor Acres chicks were randomly allocated into 6 groups with 6 replicates and 10 chicks each. The six dietary treatments consisted of a standard high-CP diet (PC), a low-CP diet (NC), and an NC diet with 0.5, 1.0, 1.5%, or 2.0% ESBM. The experiment lasted for 42 days. Compared to PC, NC showed decreased (p < 0.05) average daily gain (ADG) in broilers from 22 to 42 days and from 1 to 42 days, while increasing levels of ESBM quadratically increased (p < 0.05) ADG from 1 to 42 days. Feed cost and total revenue in the NC were lower (p < 0.05) than that in the PC, while supplementation with ESBM in the NC linearly increased (p < 0.05) net profit and economic efficiency in broilers. There were significant differences (p < 0.05) in the liver, proventriculus and gizzard indices between the PC and NC groups, and supplementation with ESBM linearly increased (p < 0.05) the relative weights of liver, pancreas, proventriculus and gizzard in broilers at 42 days of age. The PC group had a higher cecal acetic acid concentration at 21 days and propionic acid concentration at both 21 and 42 days than the NC group (p < 0.05). Cecal acetic acid and propionic acid concentrations linearly increased (p < 0.05) with increasing levels of ESBM in broilers at 42 days of age. No significant differences in ACE, Chao1, Shannon and Simpson indices were observed among groups (p > 0.05), while the cecal abundances of Bacteroides, Faecalibacterium and Clostridium IV increased (p < 0.05) with the increasing level of ESBM in the low-CP diets. In conclusion, feeding ESBM improved economic efficiency, digestive organ development, cecal fermentation and microbial community composition, and up to 2.0% ESBM addition had no negative effect on the growth performance in broilers fed low CP diets.

Isocaloric diets with varying protein levels affected energy metabolism in young adult Sprague-Dawley rats via modifying the gut microbes: A lipid imbalance was brought on by a diet with a particularly high protein content

Protein is the most important macro-nutrient when it comes to maximizing health, body composition, muscle growth, and recovery of body tissue. In recent years, it has been found that protein also plays an important role in metabolism and gut microbiota. This study was performed to investigate the effects of an isocaloric diet with different crude protein contents on the energy metabolism of Sprague-Dawley (SD) rats. Results revealed that compared with the 20% crude protein (CP; control) diet, the 38% CP diet improved serum parameters that are associated with dyslipidemia and glucose metabolic disorders in SD rats, whereas the 50% CP diet increased liver injury indicators and fatty acid synthesis-related genes and protein expression in the liver. Compared with the control diet, the 14% CP diet increased the abundance of colonic short-chain fatty acid-producing bacteria (Lachnospiraceae_NK4A136_group and Ruminiclostridium_9) and promoted colonic microbial cysteine and methionine metabolism, the 38% CP diet up-regulated colonic microbial lysine biosynthesis and degradation pathways, and the 50% CP diet down-regulated colonic mucosal cholesterol metabolism. Furthermore, the increase of multiple colonic enteropathogenic bacteria in the 50% CP group was associated with higher palmitic acid and stearic acid concentrations in the colonic microbes and lower cholesterol and arachidonic acid concentrations in the colonic mucosa. These findings revealed that the 14% CP and 38% CP diets improved rats' energy metabolism, while the 50% CP diet was accompanied by lipid metabolism imbalances and an increase in the abundance of multiple enteropathogenic bacteria.

The effect of sex and dietary crude protein level on nutrient transporter gene expression and cecal microbiota populations in broiler chickens

It is well known that male and female broilers differ in their growth performance and that many physiological factors contribute to this difference. The aim of this experiment is to investigate if there are differences between male and female broilers in cecal microbiota and nutrient transporter gene expression and if these differences play a role in the growth performance of broilers. The possible effect of protein level and its interaction with sex on microbiota and expression of the nutrient transporters were also investigated. Samples were collected from male and female birds fed either standard crude protein (SCP) or reduced crude protein diets (RCP) at the age of d 35. The experiment was designed as a 2 × 2 factorial arrangement of treatments consisting of 448 Cobb 500 broilers assigned to 32-floor pens with 4 treatments, 8 replicates, and 14 birds per pen for performance measurements. The factors were sex (male or female) and dietary crude protein (CP) level (standard or reduced). Body weight gain (BWG), feed intake and feed conversion ratio were recorded for each pen. Sex had a significant effect on BWG and FCR (P < 0.001) where males had a significantly higher BWG and better FCR compared to females. There was a significant interaction between sex and protein level on feed intake (FI) (P < 0.05), where male birds had a higher FI compared to female birds only when the birds were fed SCP but not RCP diets. There was a significant interaction between CP level and sex on the expression of CAT2 (P = 0.02) and PEPT2 (P = 0.026) where the genes were significantly upregulated in females but only when the RCP diet was fed. The RCP diet upregulated the expression of BoAT (P = 0.03) as a main effect. Female birds had significantly higher expression of the PepT-2 gene compared to the males. The alpha diversity of the cecal microbiota showed differences among the treatments. The Shannon diversity index was statistically higher (P = 0.036) for males fed the SCP diet and the Chao1 index for evenness was statistically higher (P = 0.027) in females fed the SCP diet. There was also a difference in the relative abundance of the 15 most common genera found in the cecal content of the broilers in this experiment and lastly, the differential composition of microbiota between the different treatments was also significantly different. This study suggests that chickens are able to compensate for a reduction in AA substrates when fed a low CP diet through the upregulation of certain AA transporters, females may adapt to low CP diets better by such upregulation compared to males, and lastly, sex has an effect on the cecal microbial population and these differences contribute towards the performance differences between male and female broilers.