• Asian-Australasian Journal of Animal Sciences
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• v.11 no.4
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• pp.391-397
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• 1998

The present study was conducted to examine the effects of dietary protein (20, 22, 24%) with a constant protein-to-energy ratio on clenbuterol-induced performance in broilers. The protein-to-energy ratio was based on adequate level (22% protein, 3,100 kcal of energy). Female broiler chickens were used for a $3{\times}2$ factorial arrangement and fed diets with or without 1 ppm clenbuterol from 14- to 32-days of age. Feed efficiency improved with increasing dietary protein level, regardless of clenbuterol treatment. The dietary clenbuterol increased weights of breast and leg muscles (gastrocnemius and peroneus longus), and clenbuterol markedly reduced protein content of leg muscles in chickens fed the 20% protein diet, but did not in chickens fed the 22 and 24% protein diets. Feeding the 24% protein diet with clenbuterol improved the protien accretion (peroneus longus) by 8.4%. Clenbuterol decreased DNA content and increased the protein/DNA ratio in breast muscle regardless of dietary protein intake. Clenbuterol had no effect on RNA content in both breast and leg muscles. The present results demonstrated that various protein levels which retain the same protein-to-energy ratio in the diet markedly alter the protein accretion induced by ${\beta}$-agonist in broilers.

• Preventive Nutrition and Food Science
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• v.1 no.2
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• pp.239-243
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• 1996

Three hundred and twenty-four 1 day old chicks were used to determine the effects of fat source and energy to protein ratio on growth performance , carcass composition and the efficiency on nutrient utilization. Chicks were assigned. in a completely randomized design, to 3*3 factorial arrangement of treatments. Chicks received one of three fat sources (n0 fat, tallow, corn oil) and one of three energy to protein ratios(16, 14 and 12kcal ME/g CP). All diets were formulated to be isocaloric(3.2Mcal ME/kg diets) using published ME values for the diet ingredients. Addition of tat to the diet increased ADG, average daily feed intake, and gain to feed, Chicks fed diets containing fat had increased percentage body DM and ether extract(EE), but percentage CP was not different, Chicks fed diets containing fat had increased efficiency of protein and energy deposition. Addition of fat ad either fallow or corn oil yielded similar results. Reducing the energy to protein ratio of the diet did not affect ADG or gain to feed, but tended to decrease average daily feed intake(p=0.80), as well as resulting in linear(p<0.05) reductions in body percentage DM., EE and also total EE. Increasing the energy to protein ratio did not affect percentage or total body Cp. Adding fat to poultry diets improved growth performance and the efficiency of growth chicks. Decreasing the energy to protein ratio did not affect growth performance, but reduced EE in the body of Chicks.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.11
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• pp.1629-1634
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• 2008

A trial was conducted to determine the effect of low crude protein (CP) diets with constant metabolizable energy to crude protein (ME:CP) ratio on growth, body composition and nutrient utilization of broiler chicks from 1 to 26 days of age. Four dietary treatments having four levels of CP and ME as 23, 22, 21 and 20% and 3,036, 2,904, 2,772 and 2,640 kcal/kg, respectively, were formulated and a ME:CP ratio of 132 was maintained in all the diets. Digestible lysine was maintained at 1.10 of the diet. A total of 1,760 day-old Hubbard broiler chicks were randomly divided into 16 experimental units and each diet was offered to four experimental units at random. Feed intake was increased (p<0.05) while weight gain and feed conversion ratio were adversely affected (p<0.05) when the diets with low CP and ME were fed to broilers. Total protein intake and total ME intake were linearly decreased (p<0.05) and protein efficiency ratio and energy efficiency ratio were lower (p<0.05) than in the chicks fed dietary regimen with 22% CP and 2,904 kcal/kg ME. The whole body analysis of the birds revealed that chicks fed the lowest dietary regimens retained less (p<0.05) nitrogen and more ether extract than chicks fed the control diet, however, body dry matter, total body ash and fat free body protein were not affected. Similarly, protein and energy utilization were also unaffected by the dietary treatments. In summary, chicks fed low CP diets with constant ME:CP ratio grew slower, used feed less efficiently and retained less protein and more body fat than chicks fed the control diet.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.1
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• pp.31-35
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• 1996

An experiment was conducted on rainbow trout(Oncorhynclus mykiss) for eight weeks to investigate the growth performance of the fish fed with different dietary protein with constant diet energy of $20kJg^{-1}$. Four diets containing 25, 30, 35 and 40% crude protein were used. The highest mean final weight was obtained for the fish fed with diet having 35% protein. Growth performance in terms of Specific Growth Rate (SGR), Food Conversion Ratio (FCR) and Protein Efficiency Ratio (PER) were calculated for each diet. There were no significant differences in SGR but the highest value was exhibited by fish fed with 35% protein diet. Significant differences were found among FCR of different diets. Diets with 35 and 40% crude protein gave better FCR value than that of 25 and 30% crude protein. Although significant differences were not found between PER of different diets but PER of diet with 35% protein was found to be better than PER of both high and low protein diets (diets of 40 and 30% crude protein). It is concluded that diet having 35% protein with protein energy ratio of $17.53mgkJ^{-1}$ was suitable for rainbow trout (O. mykiss) among the protein spectrum used.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.4
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• pp.868-876
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• 2014

This study was conducted to estimate the optimum dietary protein to energy (P/E) ratio in juvenile river puffer. Nine experimental diets were formulated with three energy levels and three protein levels at each energy levels. Three energy levels of 3000, 3750 and 4500 kcal diets were included at 45, 50 and 55% crude protein (CP) levels, respectively (45P3000, 45P3750, 45P4500, 50P3000, 50P3750, 50P4500, 55P3000, 55P3750 and 55P4500). Fish averaging $3.43{\pm}0.02$ g randomly were fed the experimental diets in triplicate groups for 8 weeks. Weight gain of fish fed the 50P4500 diet were significantly higher than that of fish fed the 45P3000, 45P3750, 45P4500, 50P3000 and 50P3750 diets (P<0.05), but there was not significantly different from that of fish fed the 50P4500, 55P3750 and 55P4500 diets. Feed efficiency of fish fed the 50P4500 diet were significantly higher than that of fish fed the 45P3000, 45P3750, 45P4500, 50P3000 and 50P3750 diets (P<0.05), but there was not significantly different from that of fish fed the 50P4500, 55P3000, 55P3750 and 55P4500 diets. Protein efficiency ratio of fish fed the 45P3000 and 45P3750 diets was higher than that of fish fed 50P4500 and 55P4500, but there was not significantly different from that of fish fed the 45P3000, 45P3750, 45P4500, 50P3000, 50P3750, 55P3000 and 55P3750 diets. Based on weight gain, feed efficiency and specific growth rate, diets containing energy levels 4500 kcal/kg diet had an optimum P/E ratio of approximately 111 mg protein/kcal (50% crude protein) in juvenile river puffer.

• Korean Journal of Poultry Science
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• v.41 no.4
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• pp.313-322
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• 2014

Evaluation of energy in the diet is very important in animal nutrition because food intake is strongly influenced by the energy content of the diet. This means that the intake of other nutrients, such as amino acids, is affected by their ratio to energy content. Poultry can control their energy intake over a range of energy: protein ratios. Energy: protein ratio also affects the growth and body composition. Therefore we need to know what extent the relationship between energy and dietary protein influences the bird's performance. To predict the energy value of the diet or its chemical constituents, researchers have been working on modelling using the equations of the major biochemical pathways in terms of ATP generation and utilization. The activity of feeding and the metabolism caused by digestion and assimilation of food increase the animal's heat production and it can be measured by calorimetry technique. Theoretically, surplus amino acids which are not needed for protein synthesis stimulate an additional increase in metabolic rate and lead to increased energetic costs of catabolism and excretion. However, it has sometimes been shown that there was no measurable diet-induced thermoregulatory effect when an imbalanced amino acid mixture was fed. All these aspects are discussed in this review.

• Korean Journal of Community Nutrition
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• v.10 no.6
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• pp.880-891
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• 2005

The purpose of this study was to investigate nutrients intakes and nutritional quality of Adults and Elderly People in an island area (Wando). A three-day dietary intakes survey, using a 24 hour recall method was obtained from 187 subjects aged 46 to 84 (mean age 65.3) living in an island area (Wando). Nutient intakes were analyzed using CAN-Pro soft program and compared to Korean RDA. The quality of nutrients was assessed by analyzing nutrient adequacy ratio (NAR), mean adequacy ratio (MAR), and index of nutritional quality (INQ). The average daily mean energy intakes were 1869.0 kcal for males and 1943.9 kcal for females, respectively. Daily intakes of protein for males and females were 28.0 and 30.4 g and those of fat were 31.5 and 28.51 g, respectively. Nutrient consumed below $75\%$ of Korean RDA was protein, vitamin A, Ca and Zn in both males and females. Average CPF ratio of males and females were 78.8 : 6.0 : 15.1 and 80.0 : 6.4 13.4, respectively. Energy intake ratio from protein was significantly higher in over 60 years males. Carbohydrate dependency decreased with age. Protein dependency increased with age. Nutrient adequacy ratio (NAR) of energy, protein vitamin A and vitamin E were increased with age in males. The mean adequacy ratio (MAR), an index of overall dietary quality, were not significantly different by age group. Average MAR for males and females was 0.77 and 0.78, respectively. The index of nutritional quality (INQ) showed the tendency to decrease with age. Especially, there were significantly decreases in INQ of all nutrients, except protein, with age. Based on these results, it is evident that people in the island area did not consume enough nutrients. Specially, dietary intake of protein, vitamin A, vitamin E, and Ca were not adequate. (Korean J Community Nutrition 10(6) : $880\∼891$, 2005)

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.2
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• pp.232-236
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• 2008

This experiment was performed to investigate the effects of two energy levels and four lysine:digestible energy (DE) ratios on the apparent digestibility of nutrients in finishing pigs. The experiment was conducted using a $2{\times}4$ randomized complete block (RCB) design with three replicates. Twenty-four cross-bred finishing barrows ((Landrace${\times}$Yorkshire)${\times}$Duroc) with an average body weight of $64.2{\pm}0.69kg$ were assigned to one of eight treatments. Each barrow was placed in an individual metabolism crate and dietary treatment and water was provided ad libitum. Diets were designed to contain lysine:ME ratios of 1.5, 1.8, 2.1 and 2.4 g/Mcal at 3.35 and 3.6 Mcal/kg of diet in a $4{\times}2$ factorial arrangement. Dry matter (DM), ash, Ca and P digestibility were not affected by energy density or lysine:DE ratios. Crude fat digestibility increased as the energy density increased from 3.35 to 3.6 Mcal of DE/kg. Increasing the lysine:DE ratio also increased crude protein digestibility. There were no interactions between energy density and lysine:DE ratio in terms of nutrient digestibility. Nitrogen excretion via feces was not affected by energy density and lysine:DE ratio, while nitrogen excretion via urine was significantly affected by energy density and lysine:DE ratio. The apparent digestibility of all amino acids except for isoluecine, arginine and aspartic acid as well as average values of essential amino (EAA), non-essential amino acids (NEAA) and total amino acid digestibility (p>0.05) were not affected by energy density. The apparent digestibility of all amino acids except for leucine, proline, alanine and tyrosine, NEAA and total amino acid digestibility were significantly affected by lysine: DE ratio (p<0.05). Interactive effects of energy and lysine:DE ratio also significantly affected amino acid digestibility except for isoleucine, alanine, cystine, leucine, phenylalanine, glutamine and proline (p<0.05). In conclusion, these results suggest that maintaining the appropriate lysine:DE ratio becomes more important as the energy density of the diet increases. Consequently, increasing the lysine:DE ratio can result in increased crude protein digestibility and urinary nitrogen excretion, although apparent protein digestibility and nitrogen excretion were not affected by energy density Furthermore, increasing the lysine:DE ratio also increased the apparent digestibility of essential amino acids, except for leucine, regardless of energy density. The optimum lysine:DE ratio for maximum essential amino acid digestibility of the $64.2{\pm}0.69kg$ pig is approximately 2.4 g of lysine/Mcal of DE.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.2
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• pp.365-368
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• 1992

The experiment was carried out to estimate the energy and protein requirements of Khaki Campbell $\times$ Thai Native laying ducks. To estimate the energy requirement, 5 experimental diets were formulated at levels of 2.70, 2.75, 2.80, 2.85 and 2.90 Mcal ME/kg. These diets were equal in ME/CP ratio (170/l). A total of 150 18-week old laying ducks were assigned to 5 energy level treatments, each comprising 3 replicates of 10 birds each, and they were fed the diets for 18 weeks. To estimate the protein requirement, 90 18-week old laying ducks were divided into 9 groups of 10 birds each, and they were assigned to 3 protein level treatments, each comprising 3 replicates. The levels of protein in the diets were 13.5%, 15.0% and 16.5%, and all diets were isocaloric (2.8 Mcal ME/kg). As a result, the 16.5% protein diet gave significantly better egg production than the 13.5% and 15.0% protein diets, however, no significant difference in egg production was found among the energy levels. Feed cost to produce 1k eggs was lower in the 2.70 Mcal and 16.5%protein diets than in the higher ME and lower protein diets.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.8
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• pp.1159-1163
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• 2006

This experiment was performed to examine the influences of high ambient temperature on milk production, nutrient digestibility, energy and protein sufficiency ratio, and plasma metabolites concentration in lactating cows. In a $2{\times}2$ crossover design, four multiparous lactating Holstein cows were maintained in a chamber under treatment of constant moderate ($18^{\circ}C$) ambient temperature (MT) or high ($28^{\circ}C$) ambient temperatures (HT). The DMI and milk protein yield were significantly lower in HT (p<0.05). The milk yield, milk lactose yield, and milk SNF yield tended to be lower in HT (p<0.10). No statistical differences for 4% fat-corrected milk and milk fat yield were observed. Rectal temperatures were significantly higher in HT than MT (p<0.05). The apparent DM, OM, ether extract, CF, and ash digestibility did not differ between treatments. On the other hand, the apparent CP digestibility was increased significantly (p<0.05) and nitrogen free extract tended to increase (p<0.10) in HT. The sufficiency ratio of ME and DCP intake for each requirement tended to be lower in HT than in MT (p<0.10). Concentrations of total protein (TP), albumin, and urea nitrogen in plasma did not differ between treatments. Plasma 3-methylhistidine (3MH) concentration as a marker of myofibrillar protein degradation tended to be higher in HT (p<0.15). In conclusion, high ambient temperature was associated with a lower energy and protein sufficiency ratio, and decreased milk protein production, even though the body protein mobilization tended to be higher.