Effect Of Different Protein Levels Research Articles

Molecular Characterization and Nutrition Regulation of the Glutamine Synthetase Gene in Triploid Crucian Carp

Glutamine synthetase (GS) is a key enzyme that catalyzes the synthesis of glutamine from glutamate, which plays a role in the promotion of muscle cell growth and in improving the flavor of meats. In this study, a GS gene encoding 371 amino acids was cloned from triploid crucian carp and showed the highest level of similarity with the GS gene found in Cyprinus carpio. Meanwhile, GS was differentially expressed in different tissues, and its day–night expression changes showed obvious oscillation. Additionally, the effects of glutamate and glutamine on GS expression in muscle cells were investigated in vitro and in vivo. We found that its expression was obviously increased due to high levels of glutamate (2 mg/mL) but decreased by glutamine in vitro. However, it was significantly promoted by glutamate and glutamine in vivo, with an optimal concentration of 2%. Furthermore, the use of lysine–glutamate dipeptides as feed additives also had a positive influence on GS expression (the optimal concentration is 0.8%). Finally, we explored the effects of different protein levels and sources on the expression of GS, and the results demonstrated that GS had the highest expression at the 35% protein level, but no significant differences were observed in the different protein sources between the fish meal diet (FM) and the mixed diet comprising soybean meal and rapeseed meal (SM). This study sheds new light on the regulation of GS in teleost fish and provides new perceptions and strategies for the formulation of high-quality feed for triploid crucian carp.

Effects of Diets With Different Protein Levels on Lipid Metabolism and Gut Microbes in the Host of Different Genders.

The purpose of this experiment was to investigate the effects of different protein levels on lipid metabolism and gut microbes in mice of different genders. A total of 60 mice (30 female and 30 male) were randomly assigned to six groups and fed female mice with low protein diet (FLP), basal protein diet (FBD), and high protein diet (FHP). Similarly, the male mice fed with low protein diet (MLP), basal protein diet (MBD), and high protein diet (MHP). The low protein diet contained 14% CP, the basal diet contained 20% CP, and the high protein diet contained 26% CP. The results of the study showed that both basal and high protein diets significantly reduced the perirenal adipose tissues (PEAT) index in male mice compared to low protein diet (p < 0.05). For the gut, the FHP significantly increased the relative gut weight compared to the FBD and FLP (p < 0.05). At the same time, the FHP also significantly increased the relative gut length compared with the FBD and FLP (p < 0.05). The MHP significantly increased TC concentration compared with the MLP (p < 0.05), and the MBD tended to increase TC concentration compared with the MLP in serum (p = 0.084). The histomorphology result of the jejunum and ileum showed that a low protein diet was beneficial to the digestion and absorption of nutrients in the small intestine of mice. While different protein levels had no effect on the total number of fecal microbial species in mice, different protein levels had a significant effect on certain fecal microbes in mice, the absolute abundance of Verrucomicrobia in the feces of male mice was significantly higher in both high and basal protein diets than in the low protein diet (p < 0.05). The high protein diet significantly reduced the absolute abundance of Patescibacteria in the feces of female mice compared to both the basal and low protein diets (p < 0.05). The absolute abundance of Patescibacteria in male feces was not affected by dietary protein levels (p > 0.05). Taken together, our results suggest that a low protein diet can alter fat deposition and lipid metabolism in mice, and that it benefited small intestinal epithelial structure and microbes.

Effects of different protein levels on growth performance and stress parameters in beef calves under heat stress

This study investigated the effects of dietary protein levels under various heat stress (HS) conditions on the growth performance and stress parameters in Korean native beef calves. Male calves (n = 40; initial BW = 202.2 ± 3.31 kg) were randomly assigned to climatic-controlled chambers with 3 × 3 factorial arrangements. Calves were assigned into three dietary protein levels (low protein; LP = 12.5%, medium protein; MP = 15%, and high protein; HP = 17.5%) and three HS levels [mild: temperature-humidity index (THI) = 74 to 76, moderate: THI = 81 to 83, and severe: THI = 89 to 91] with control (threshold: THI = 70 to 73 and dietary protein level 12.5%). The calves were subjected to ambient temperature (22 °C) for 7 days and subsequently to the temperature and humidity corresponding to the target THI level for 21 days. The data were analyzed using the repeated-measures analysis by the GLM procedure of SAS. As a result, average daily gain (ADG) was decreased (P < 0.05) under severe HS level compared to the mild and moderate HS stress levels. However, HP increased ADG (P < 0.05) than moderate levels (LP) and severe levels (LP and MP). Under different HS levels (mild, moderate, and severe), HR, RT, and blood cortisol were increased (P < 0.05) compared to a threshold level, but no differences were observed in the parameters among various protein levels. Varied HS levels decreased the levels of blood glucose, NEFA, and amino acids (AAs) (lysine and glutamic acid) compared to a threshold (P < 0.05). But, the HP group resulted in increased (P < 0.05) levels of blood glucose, NEFA, and AAs (lysine and glutamic acid) compared to LP and MP groups under severe HS stress. The expression level of the HSP70 gene in peripheral blood mononuclear cell (PBMC) and hair follicles was increased (P < 0.05) following an increase in moderate and severe HS levels. Also, HSP70 gene expression in the HP group was decreased (P < 0.05) compared with LP and MP groups under intense HS level. Overall, HS in Korean native beef calves exhibited negative effects on ADG, blood glucose, NEFA, and AA profile. However, 17.5% of dietary protein (HP) could compensate for the growth of heat-exposed Korean native beef calves through the regulation of homeostasis by protein and energy metabolism. Also, it was evident that adequate protein (HP) is used as a major nutrient for HSP70 synthesis in PBMC and hair follicles causing, a boost in the immune system of heat-exposed Korean native beef calves.

Effects of dietary protein on gut development, microbial compositions and mucin expressions in mice.

Dietary protein, as an important macronutrient, widely participates in host growth and metabolism. In this study, effects of different protein levels (14, 20 and 26%) on the gut development, microbial compositions and mucin expressions were studied in C57BL/6mice. The results showed that body weight and the relative weight of stomach and gut were decreased in low-protein diet-fed mice, whereas high-protein diet significantly reduced the villus length and area of jejunum. Goblet cells number in the jejunum was reduced in the low-protein group, which was reversed by dietary a high-protein diet. In addition, high-protein diet notably reduced microbial diversity and changed the microbial compositions at the phylum level, such as Bacteroides, Proteobacteria, Actinomycetes and Deferribacteres. Furthermore, high-protein diet significantly increased mucin2, mucin3 and mucin4 expressions in the jejunum, but downregulated mucin1, mucin2, mucin4 and TFF3 in the ileum, indicating a tissue-dependent manner. Together, high-protein diet may impair gut development, microbial balance and mucin system, and a low-protein diet is suggested to promote a healthy lifestyle. Mucin influenced gut development (villus index and goblet cell number) through remodelling gut microbes, as low and high protein levels resulted in contrary expression levels of mucin in jejunum and ileum.

Diet containing 35% crude protein improves energy balance, growth, and feed conversion in the Amazon river prawn, Macrobrachium amazonicum

A technological package has been developed in South America for culturing prawn Macrobrachium amazonicum; however, little information is available on its physiology and diet. We investigated the effect of different protein levels in the diet (32%, 35%, and 38% crude protein -P) on the feed conversion rate (FCR), hepatosomatic index (HSI), and energy balance, calculated through the energy ingested and channeled toward growth, metabolism, feces, excretion, and exuviae for 30 days. Animals fed with 35% P channeled more energy toward growth (8.6% of energy intake), defecated less (only 5% of food intake), and improved FCR (about 1.2), and accumulated more energy in the body. In contrast, animals fed with 32% P channeled more energy into feces (36% of energy intake), and those fed with 38% P had the worst FCR and HSI. Regardless of the diet, ingested energy was mainly channeled toward metabolism (63–91%). Thus, we conclude that the protein content affects the variables evaluated and that the diet containing 35% P is a good alternative to optimize the use of energy channeled toward growth and minimize energy loss via excretion.

Effects of different protein levels on Pacific white shrimp (Penaeus vannamei Boone, 1931) farming in a system with limited water exchange

Limited water exchange system is an environmentally friendly system that pursues the goals of sustainable aquaculture and is used in modern aquaculture. In the present study, the effect of different levels of dietary protein on water quality, growth performance and biochemical composition of microbial mass in the system with limited water exchange was investigated. Western white shrimp juveniles with an average weight of 2.5 g were studied in fiberglass tanks with a volume of 160 liters and a density of 1 fish per liter for 5 weeks. Four experimental treatments with different levels of dietary protein including 40, 36, 33 and 30% were considered in the system with limited water exchange. The results of the present study showed that the amounts of dissolved oxygen, pH, total ammonia nitrogen (1.11 mg/l) are higher in the treatment of diet with 40% protein. Growth performance in 33% and 36% protein showed a significant difference compared to 30% and 40% level of protein (P <0.05), so that higher values were observed in 33% and 36% protein treatments. The biochemical composition of the microbial mass was affected by different dietary proteins (P <0.05) and higher amounts of lipid (2.17%) and ash (35.44% of dry weight) were observed in the treatment with 30% protein. According to the present study, it was found that different dietary proteins affect water quality, growth performance of western white shrimp and microbial mass composition and the optimal values in the diet are 33% and 36% of protein.

Effect of dietary protein on growth performance, and serum biochemical index in late pregnant Hu ewes and their offspring

The purpose of this study was to investigate the effects of different protein levels in late pregnancy on ewe and lamb growth performance, serum biochemical indexes. Thirty-three ewes (46.4 ± 1.38 kg initial weight) were randomly divided into 3 groups, with 11 ewes in each group. The protein levels of three diets formulated to provide components to meet 10.00 MJ/kg ME requirements diets were: 10.12%, 11.26%, 12.4%. Ewes were raised from the 90th day of pregnancy to the end of delivery, and the lambs were weaned at 60 days. Dietary protein levels had significant effects on blood urea nitrogen, glucose, ammonia nitrogen and triglyceride of ewes (p < 0.05). The height, chest depth, chest circumference, straight crown hip length and curved crown hip length of lambs decreased at first and then increased with the increase of protein. The body length, chest circumference, head width and head length of weaned lambs decreased at first and then increased with the increase of protein. The results showed that when the dietary protein level was increased to 12.4%, the amino acid, glucose and fat metabolism of ewes were affected. The body size development of lambs was better than 10.12% and 11.26% proteins.

Determination of Optimum Protein and Energy Levels for Broiler Chicks in the Tropics

THREE experiments were conducted to investigate the effects of different protein levels (17, 20, 23 and 26%) and energy levels (2800, 3000 and 3200 KCals/Kg diet) on the performance of broiler chicks in the tropics. Maximum weight gains and efficiency of feed conversion were obtained on the rations containing 23 or 26% protein. As the dietary energy level increased, there was a slight depression in weight gain. The best performance of chicks was obtained on the rations containing 2800 KCals/Kg diet. Feed intake was observed to be inversely related to energy content, although in most cases not significantly so at each protein and energy series. Generally birds were observed to meet their energy requirements. From these studies, a protein level of 23 or 26% and energy level of 2800 or 3000 K Cal/Kg diet may be tentatively recommended for a tropical country like Nigeria.

Effect of different protein levels with ideal amino acid ratios to digestible lysine on performance of 61-72 weeks White Leghorn layers

Effect of different protein levels with ideal amino acid ratios to digestible lysine on performance of 61-72 weeks White Leghorn layers

PRODUCTIVITY OF RAINBOW TROUT DEPENDING ON PROTEIN LEVELS IN PRODUCTIVE FEED

The article considers the efficiency of using complete feeds with different levels of protein in rearing commercial rainbow trout. The purpose of the experiment was to establish the effect of different protein levels in nutrition of two-year old trout on its productivity. For this purpose, five experimental groups were formed by the method of analogues. During the equalizing period, the experimental fish consumed feed of the control group. In the main period, the protein level in trout feed ranged from 44 to 52 % per 1 kg. As a result of the studies it was established that the increase of protein content in compound feed from 48 to 52 % leads to an increase in the weight of commercial fish by 13.0 % (p &lt; 0.001), an increase in its growth intensity – by 7.4-16.7 %, while the reduction of protein in feed to 44 % leads to a reliable (p &lt; 0.05) reduction in trout weight by 9.4 %, and a decrease in its growth intensity - by 6.5-12.1 %. It is proved that different levels of experimental trout’s protein nutrition have a highly reliable (p &lt; 0.001) effect on the growth of marketable fish - the share of this factor’s influence is 89.8 %. Analysis of the feed costs, proves that using combined feed with 52 % protein for feeding two-year old trout, leads to a decrease in feed costs per 1 kg of weight gain by 5.1 %, whereas reducing this index to 44% causes increase of feed costs by 6.4 % per a unit of product, compared to feeding fish with production feed having the protein content of 48 %. At this, the preservation of experimental fish was high enough and made 94.3 to 96.2 %. In rearing trouts according to the criteria of maximum productivity, it is recommended to feed commercial trout with production combined feeds with the protein level of 52 %, whereas, in production according to the economic optimization criteria, this index should make 48 %.

Fermentation and Metabolism of Dietary Protein by Intestinal Microorganisms.

Dietary protein is linked to the intestinal microorganisms. The decomposition of dietary protein can provide nutrients for microbial growth, which in turn can ferment protein to produce some metabolites. This review elaborates that the effects of different protein levels and types on intestinal microorganisms and their metabolites fermented by intestinal microorganisms, as well as the effects of these metabolites on organisms. It is well known that intestinal microbial imbalance can cause some diseases. Dietary protein supplementation can alter the composition of intestinal microorganisms and thus regulates the body health. However, protein can also produce some harmful metabolites. Therefore, how to rationally supplement protein is particularly important.

EFFECT OF DIFFERENT LEVEL OF PROTEIN ON GROWTH PERFORMANCE, SURVIVAL RATE, DIGESTIVE ENZYME, AND BODY PROTEIN COMPOSITION OF JUVENILE BESENG-BESENG FISH (Marosatherina ladigesi)

Marosatherina ladigesi’s original habitat is in the freshwater of South Sulawesi as endemic fish in the wallacea zone Indonesia, with a local name called beseng-beseng fish. M.ladigesi was already in the category of at threat of extinction.The purpose of this study was to investigate the effect of different protein levels on survival rate, growth performance, body protein composition and enzyme activity of protease, lipase and amylase of beseng-beseng fish. The research method was using Completely Randomized Design with three treatments and three replications. Treatment of the study: protein content of feed A: 40%, B: 50% and C: 60%. Fish maintenance takes 90 days. The results showed that protein content had a significant effect (P&lt;0,05) on absolute body growth, specific growt rate, survival rate, body protein composition and protease enzyme activity of juvenile beseng-beseng fish. The best growth performance is obtained at 50% and 60% protein content, while the survival and body protein composition and the best protease enzyme activity at 60% protein content.

Effects of Different Protein and Energy Levels in Mixed Feed on Growth Performance and Reproduction Characteristics of Heifers

Background: In this study, the effects of different protein and energy levels in mixed feed on growth performance and reproduction characteristics of heifers were investigated. Method: The material of the study consisted of 36 Holstein Friesian (black pied) breed cattle at the age of 6 months and average live body weight of 156.65 kg and the experiment was continued for 8 months. During the experiment, four different feeds containing 16% CP - 2500 kcal / kg ME for the 1st group, 16% CP - 2700 kcal / kg ME for the 2nd group, 18% CP - 2500 kcal / kg ME for the 3rd group, 18% HP - 2700 kcal / kg ME for the 4th group were given at 1.5% of the live weight of heifers. (Where CP and ME stand for Crude Protein and Metabolizable Energy, respectively). As roughage, an equal amount of straw and alfalfa hay mixture was given. Result: As a result of this study, the effects of the different protein levels on live body weight and body measurements (body length-BL, withers height-WH, hip height-HH, hip width-HW, body depth-BD, chest girth-CG) were not found significant (P is greater than 0.05). Similarly, the effects of different energy levels on body weight and body measurements (P is greater than 0.05) and protein X energy interaction in terms of live body weight and size were also not found significant (P is greater than 0.05). Regarding the reproductive properties, the differences between the groups in terms of the effect of different protein and energy levels on the first estrus age were found statistically significant (P is less than 0.05). As a result of the analysis made in terms of heifers age during the first insemination, the difference was found to be statistically significant (P is less than 0.05). The effect of different protein and energy levels on the conception rate in the first insemination was found significant (P is less than 0.05). As a result, it was concluded that affordable mixed feed combinations can be used within the limits of mixed feed combinations containing 2500-2700 kcal / kg ME and 16-18% CP, which were given in the investigation; however, low energy-high protein combinations would give more positive results considering their effects on the reproductive performances and conception rates at first insemination.

INFLUENCE OF LOW-PROTEIN LEVELS FORTIFIED WITH METHIONINE AND ENERGY ON PRODUCTIVE AND REPRODUCTIVE PERFORMANCE OF SILVER MONTAZAH LAYING HENS

The objective of the present experiment to determine the extent to which the crude protein (CP) content of laying hen diets can be reduced, based on fortified with methionine (Met.) to reach a level of sulfur amino acids equal with high-protein level and their effects on productive and reproductive performance of silver Montazah laying hens during 24-40 wks of age. One hundred and eighty hens 24-weeks old were housed in individually cages in factorial experimental design (2X3) involves 30 birds in each treatment. The experimental diets were formulated with two dietary metabolizable energy levels (low energy = 2700 and high energy = 2850 kcal ME / kg diet) and three dietary protein levels 14% low crude protein; 16% moderate crude protein and 18% high crude protein. The diets of 14 and 16% CP were fortified with methionine to reach the same level of SAA 18% CP-diet. Feeds and water were offered ad libitum. Fertility and hatchability percentage were determined at 37, 38 and 39 wk of age. All hens from each treatment group were artificially inseminated twice a week with a fixed volume of diluted semen (1:1) from cockerels fed diet containing 16% CP and 2750 kcal/kg diet. Results are summarized as follows: Significant increases were observed in final body weight (FBW), body weight change (BWC), metabolizable energy efficiency ratio (EER) feed conversion ratio (FCR), Egg production parameters; egg number (EN), egg weight (EW), daily egg mass (EM), hen-day egg production rate% (HDEP), cholesterol level in blood plasma and economic efficiency of feed parameters (EEF) due to feeding on high-energy diets, while birds fed on low-energy diets resulted in significantly (P≤0.01) increased in feed intake, daily protein intake, daily energy intake and daily methionine intake than that fed high-energy diet. The same manner was observed in respect of protein levels, where increasing protein content in the diet had a significant improvement (P≤0.01) in final body weight, change (BWC), daily protein intake, energy efficiency ratio, feed conversion ratio, egg number, egg weight, egg mass, hen day egg production rate, AST, and ALT in blood plasma. Interaction between energy and protein levels were significant effects on most studied traits, there were positive effects of different protein levels at high energy level on body weight, body weight change, energy efficiency ratio, feed conversion, egg number, daily egg mass, hen-day egg production rate%, egg fertility%, hatchability%, chick weight, most blood traits and economic efficiency of feed. However, neither energy nor protein levels significantly affected on egg quality, egg fertility percentage and chick weight. Based on performance outcomes hens fed high-energy diet with 14% or 16% protein level fortified with DL-methionine succeed in recording egg number and hen-day egg production rate like those fed on 18% protein. It could be concluded that reducing protein level fortified with DL-methionine in Montazah laying hens diets had beneficial effects on some traits but not all traits. From economic analysis of this study it can be used diets containing 2850 kcalME/kg diet with 14% or 16% CP fortified with methionine in feeding Silver Montazah laying hens during 24-40 weeks of age without negative effect on profitability.

Effects of Different Protein Levels on the Nitrogen Balance, Performance and Slaughtering Traits of Cinta Senese Growing Pigs.

Simple SummaryCinta Senese is a local Tuscan pig breed often reared extensively and characterized by slower growth rates compared to commercial pig breeds. It is thus frequent that the use of feed formulations based upon commercial breed requirements might provide too much protein for this breed. The aim of the present study was to assess protein requirements during the growing phase of Cinta Senese pigs (from 28 to 65 kg). Four dietary formulations, providing 12%, 14%, 16% and 18% of crude protein, were tested, and their effects on growth rates, lean and fat tissues deposition, carcass composition and nitrogen excretions, were evaluated in order to identify the best protein level to be adopted. Results showed that the animals which were fed the 12% diet were heavier, that they better exploited the dietary protein to increase the body mass and also that their urine contained the lowest amount of nitrogen. So, during the growing phase, feeding diets containing more than 12% of protein leads to a surplus in the protein intake which the animals are no longer able to convert into muscle. In conclusion, the diet providing 12% of protein resulted as being adequate for fulfilling Cinta Senese requirements during the growing phase. Identification of the actual protein requirements of Cinta Senese growing pigs could enhance the feeding management at the farm level, resulting thus in less nitrogen excretions as well as in reduced feed costs.Cinta Senese is characterized by slow growth rates, which implies different nutritional requirements compared to major pig breeds. Four different crude protein levels (120, 140, 160 and 180 g/kg on as-fed basis, denoted as CP12, CP14, CP16 and CP18) were tested to assess the optimal protein requirements of Cinta Senese pigs during the growing phase. The in vivo performance, slaughtering traits and nitrogen balance were evaluated using individual pens and metabolic crates. Increasing the protein level in feed lowered the average daily gain (from 0.76 to 0.71 kg/d), final weight (63.0 kg for CP12 versus 60.7 kg for CP16) and reduced the protein conversion efficiency (from 0.37 to 0.58). Also, protein conversion in lean protein linearly increased from CP12 (4.82) to CP18 (7.43), which implies a worsening in the protein utilization efficiency. The nitrogen balance showed higher loss of N through urine (from 0.68 g/d/kg metabolic weight for CP12 to 1.14 g/d/kg metabolic weight for CP18) as the dietary CP levels increased, and a decrease in the biological value (51.78 for CP12 versus 36.54 for CP16). The results indicated that the CP12 diet was adequate for fulfilling the Cinta Senese protein requirements during the growing phase.

Effects of different protein levels and carbon sources on water quality, antioxidant status and performance of common carp (Cyprinus carpio) juveniles raised in biofloc based system

An 8 weeks trial was performed to evaluate the effects of crud protein (CP) levels (20 and 30%) each in three carbon sources in BFT (sugarcane molasses: M, rice bran: R, M + R and control) on water quality and performance of Common carp (cyprinus carpio) juveniles. Seven hundred twenty healthy juveniles (30.5 ± 3.1 g) were randomly distributed in 24 rectangle tanks (200 L) at a density of 4.5 kg m−3 (30 fish/tank). Juveniles in BFT treatments were fed at 75% of the daily feeding rate (DFI) of control. At the end of the experiment, the results showed that among the BFT treatments, M + R in both CP level had the lowest amount of total ammonia nitrogen (TAN) in comparison with other carbon sources in CP levels. The 30% CP level and rice bran contained treatments (R, R + M) significantly increased weight gain, specific growth rate (SGR) and survival and decreased feed conversion ratio (FCR) when compared the M and control treatments (P < 0.01). The highest activity of amylase, total protease and lipase was seen in the higher CP level and R + M treatment which was coincidental with growth performance data in this group. The CP levels did not changed white blood cell (WBC) and packed-cell volume (PCV) but in comparison to low level of CP and control, the 30% CP level and R + M significantly increased red blood cells (RBC) and (hemoglobin test) HB (P < 0.05). Glucose as a stress indicator was not affected by diet CP level however the fish reared in M treatment showed a significant increase in concentration when compared with others (P < 0.01). The higher CP level improved immune response in the fish reared in BFT treatments and the highest concentration for IgM, ACH50, total protein and globulin was seen in R + M treatment which significantly differed from the control (P < 0.05). The similar trend was observed for antioxidant enzymes and the fish fed higher CP level and reared in BFT treatments had significantly better antioxidant status than the control (P < 0.05). According to normal range of CP for Common carp juveniles (35–40%), the results of this experiment suggest that microbial flocs could not compensate 15% reduction of CP in juveniles diets but using R + M as carbon source improves growth performance, immune and antioxidant status in the fish when fed 30% CP.

Effect of different protein levels on reproductive performance of snakehead murrel Channa striatus (Bloch 1793)

In this study the effect of different protein levels on reproductive performance of C.striatus was conducted. Snakehead juveniles (65.5 ± 0.2 g) were randomly distributed into nine homogenous groups of 75 fish each. Three isocaloric experimental diets differing in protein levels were prepared. The experiment lasted for 8 months and gonadosomatic index, absolute fecundity, egg diameter, number of mature oocytes, hatching rate, larval length, survival rate and amino acid and proximate composition of tissue, liver and ovary were monitored. Growth, gonadosomatic index (GSI) and absolute fecundity increased with increase in protein level. Protein and lipid content of ovary was highest in fish fed 450 g kg-1 protein. The percentage of mature oocyte, highest egg diameter, hatching rate and larval length were highest in the group of 450 g kg-1 protein. There was no significant difference between amino acids profile of muscle in all treatments. Amino acid profile in the liver showed that isoleucine, leusine, phenylalanine and tyrosine were significantly higher in fish fed 450 g kg -1 protein diet.

Carcass, Organ Weights and Egg Quality Characteristics of Guinea Fowl Layers Fed Varying Levels of Butter Fly Pea Leaf (Centrosema Pubescent) Meal.

This study was conducted to investigate the effects of different protein levels on growth of guinea fowl keets (Numidia meagris) of the same age under intensive system in a typical poultry house from 6th week to 12th week of age. They were fed commercial broiler starter for two weeks and maintained on same diet of 18% crude protein for 5 weeks of age and given water ad libitum. The birds were separated into three pens. One hundred and twenty old guinea fowls were assigned at grower period on 3 dietary protein levels of 14, 16 and 18% crude protein (CP) on same metabolizable energy level of 2800 kcal/ kg. The study conducted at the Poultry Unit of Teaching and Research Farm, Imo State Polytechnic was used to test the performance of the guinea fowl layer birds. The birds were killed at the owner’s farm by cutting the neck through the jugular vein. There was significant difference (P&lt;0.05) in feed intake between the three treatments. The internal organs for the treatments were not significantly different. Keywords: Carcass, Organ Weights, Egg Quality Characteristics, Guinea Fowl Layers, Butter Fly Pea Leaf (Centrosema Pubescent) Meal.

Carcass and Meat Characteristics of Male Bali Cattle in Indonesian Smallholder Farms Fed Ration with Different Protein Levels

The objective of research was to determine the effect of different protein levels on the carcass and meat characteristics of male Bali cattle fattened in smallholder farms. The cattle used were 18 heads aged 2 to 2.5 years with initial body weight of 229.86±12.46 kg. The experimental cattle were randomly divided into 3 treatment groups i.e., T₀, T₁, and T₂. The T₀ group cattle were fed ration according to traditional practices of fattening cattle by farmers (100% forage). The T₁ group cattle were fed ration with 12% CP and 72% TDN. The T₂ group cattle were fed ration with 15% CP and 72% TDN. The variables measured were final body weight and the characteristics of the carcass (meat, fat, and ratio of meat to bone), and meat quality including the chemical composition of the meat (protein, fat, and collagen), meat tenderness, cooking loss, water holding capacity, and degree of acidity (pH). Data were analyzed by variance analysis. Results of research showed that the final body weight, and weight of carcass, meat, and fat of T₁ and T₂ groups were similar; conversely, those parameters in T₀ group cattle were lower (P<0.05) that those in T₁ and T₂ groups cattle. The meat protein content of T₁ and T₀ groups cattle were similar; conversely, T₂ group cattle had lower (P<0.05) meat protein content compared to T₁ and T₀ groups cattle. Fat content of T₁ group of cattle was higher (P<0.05) than that of T₀ group; while moisture contents and cooking losses of T₀ group cattle were higher (P<0.05) compared to those of T1 and T₂ groups cattle. Collagen content of meat in T₁ group cattle was higher than (P<0.05) that in T₀ group cattle, but T₂ group cattle had similar meat collagen content to T₁ and T₀ groups cattle. Meat tenderness of T₁ group cattle was higher (P<0.05) compared to those of T₀ and T₂ group cattle. It is concluded that the male Bali cattle fed ration with 12% CP and 72% TDN can increase the carcass characteristics and meat quality. This proves that the productivity of male Bali cattle can be increased when fed ration with adequate protein with a balanced energy content.

Efecto del nivel de proteína en el crecimiento de Goodea atripinnis (Pisces: Goodeidae)

Background. Goodea atripinnis is an omnivorous fish that is only found in the state of Aguascalientes. Its population is being drastically reduced and its survival is considered to be threatened. To avoid its extinction, ex situ breeding programs are being implemented. To implement these programs, however, it is necessary to have feeding plans that allow the nutritional needs of this species to be met. Goals. To evaluate the effects of different protein levels in the diet (25, 30, 35, 40 and 45 % PC) on the growth of G. atripinnis. Methods. A randomized complete-block design with five treatments (protein levels) and 3 aquariums per treatment was used, each aquarium containing 20 fish. The experiment lasted 150 days. Daily feed intake and changes in weight and length of each fish were recorded every 15 days. Results. We found differences in final weight and total weight gain (p <0.05) depended on protein levels. Both the growth rate and the total food intake increased with higher levels of protein. As a result, the feed conversion rate, protein efficiency, and Fulton (K) body condition factor improved. The Gompertz model showed that high protein levels increased standard weight and that the inflection point occurred at the same weight. Conclusions. With higher protein levels, the standard weight is reached at an earlier age, leading to greater development of the fish.