• Asian-Australasian Journal of Animal Sciences
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• v.23 no.8
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• pp.1034-1042
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• 2010

This study aimed to determine the optimum dietary crude protein level in a typical diet for fattening pigs fed ad libitum under normal climate conditions in Central Vietnam. One hundred and ninety two gilts of Mong Cai local breed (MC), $F_1$ Large White${\times}$Mong Cai and $F_2$ crossbreds of (Landrace${\times}$Mong Cai)${\times}$Large White were used. At the start of the experiment, Mong Cai pigs weighed 12 kg at 11 weeks of age, $F_1$ pigs 12.1 kg at 8 weeks of age and $F_2$ pigs 12.2 kg at 8 weeks of age. Four diets differing in crude protein (CP) content (10.1, 13.1, 16.1 and 18.9% in DM) were formulated from rice bran, corn meal, cassava meal and fish meal. Calculated digestible energy content of the diets ranged from 13.5 to 13.8 MJ per kg DM. Pigs were housed individually in pens of $2.5\;m^2$ each and had ad libitum access to feed in a trough as well as water in bowls. The final weights after a growing period of 150 days were 66, 86 and 96 kg for MC, $F_1$ and $F_2$, respectively. Feed intake of MC pigs was highest at 13.1% CP while $F_1$ and $F_2$ had the highest feed intake at 16.1% CP. The results showed that for MC the maximum gain was obtained at levels between 13 to 16% CP. For the $F_1$ the maximum gain was at dietary protein levels of 16-17%. For $F_2$ the max gain was obtained at CP levels of 16 to 18%. Feed conversion was highest in MC pigs (~4.0) followed by $F_1$ (~3.3) and $F_2$ (~3.1), and within genotypes was lowest at the optimum CP level (p<0.05). Back fat thickness in MC (33.1 mm), $F_1$ (23.0 mm) and $F_2$ (20.5 mm) pigs was different and within genotypes was the lowest at intermediate CP levels. In conclusion, increasing the dietary crude protein contents in practical diets for pigs in Vietnam can increase production on small holder farms. Optimal performance for MC, $F_1$ and $F_2$ pigs is achieved at different dietary crude protein contents.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.3
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• pp.308-313
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• 2015

A $3{\times}3$ factorial study was conducted to investigate the effects of dietary protein and lipid levels on the growth, feed utilization and innate immunity of red seabream Pagrus major. Nine diets consisting of three protein levels (42%, 46% and 50% crude protein) and three lipid levels (10%, 14% and 18% crude lipid) were formulated. Triplicate groups of red seabream were fed the experimental diets to apparent satiation (5-6 times a day, from 08:00 to 18:00 h at 2-h intervals) for 10 weeks. At the end of the feeding trial, the weight gain and specific growth rate of fish fed P46L14 (46% protein and 14% lipid), P50L10 (50% protein and 10% lipid) and P50L14 (50% protein and 14% lipid) were significantly (P<0.05) higher than those of fish fed P42L18 (42% protein and 18% lipid). The feed conversion ratios (FCR) of the fish were affected by dietary lipid levels (P<0.039), but not dietary protein levels. The FCR tended to increase with increasing dietary lipid levels from 10% to 18% with the 46% and 50% protein levels. The weight gain, protein efficiency ratio, specific growth rate, feed intake and survival of fish were not affected by either dietary protein or lipid levels. Myeloperoxidase activity in the group fed P50L14 (50% protein and 14% lipid) was significantly higher than that in the group fed P42L10 (42% protein and 10% lipid) or P50L18 (50% protein and 18% lipid). However, the myeloperoxidase activity of fish was not affected by either dietary protein or lipid level. The fish fed P46L14 (46% protein and 14% lipid) and P46L18 (46% protein and 18% lipid) showed significantly higher superoxide dismutase activity than did the fish fed P46L10 (46% protein and 10% lipid), P50L10 (50% protein and 10% lipid) of P50L18 (50% protein and 18% lipid). In conclusion, the optimum protein and lipid levels for the growth and feed utilization of juvenile red seabream were 46% and 14%, respectively, and the optimum dietary protein to energy ratio was 27.4 g/MJ.

• Journal of Animal Science and Technology
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• v.47 no.5
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• pp.805-812
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• 2005

The aim of this study was to provide basic information to allow improved feeding management for velvet antler production by investigating the effects of dietary protein level on production and chemical composition of velvet antler in spotted deer(Cervus nippon). Eighteen male spotted deer of 5~6 years old were assigned to 3 unreplicated groups by production record of the previous year. Deer were fed on experimental diets at different protein level of 10%(T1), 15%(T2) and 20%(T3). Dry matter intake, crude protein intake and daily gain were increased with increasing the protein level in diets and there were significant differences(P<0.05) between groups. Although not significant, mean length of main beam tended to be longer in either left or right beam with increasing the protein level, and in girth at part of base of main beam, it was a similar pattern to the result of length. The velvet antler production was affected by dietary protein level and thus that was the smallest in T1 and the largest in T3(P<0.05). The content of crude protein in velvet antler was higher in T1 than in T3, whereas the content of crude ash in velvet antler was contrast to that of crude protein, however, there were no significant differences.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.4
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• pp.377-383
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• 2013

We ran a feeding trial to determine optimal dietary protein and lipid levels for growth of juvenile long snout bullhead Leiocassis longirostris Gunther. Eight experimental diets (P20L7, P20L14, P30L7, P30L14, P40L7, P40L14, P50L7 and P50L14) were formulated to contain 20%, 30%, 40% or 50% protein combined with either 7% or 14% lipid. Three replicate groups of fish (mean mass: 3.9 g/fish) were fed one of the experimental diets ad libitum for 8 weeks. Survival of fish fed the P20L14 diet was lower than that of fish fed the P40L14, P50L7 and P50L14 diets. Growth of fish fed diets containing 7% lipid increased with increasing protein level (up to 50% protein); growth of fish fed diets containing 14% lipid increased with increasing protein level (up to 30% protein). The feed efficiency of fish fed a diet with 50% protein and 7% lipid was higher than that of other groups. Whole body moisture and lipid contents were affected by dietary lipid level but not by dietary protein level. The crude lipid contents of fish fed 14% lipid diets were higher than those fed 7% lipid diets across all protein levels (other than the 50% level). Thus, under our experimental conditions, an increase in dietary protein level improved growth and feed efficiency of fish; a diet containing 50% protein with 7% lipid was optimal for growth and effective feed utilization in juvenile long snout bullhead.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.4
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• pp.525-534
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• 2001

A total of 120 pigs were used to investigate the effects of yucca extracts on the growth performance, nutrient digestibility, nutrient excretion and carcass characteristics of finishing pigs fed different levels of dietary protein. Pigs were allotted into $2{\times}3$ factorial design by the supplementation of yucca extracts (YE, 0 and 120 mg/kg) and 3 levels of dietary protein (14, 16, 18% for early finisher and 12, 14, 16% for late finisher for low, medium and high protein diet, respectively). During the early finishing period (51~76 kg BW), no significant difference was found in growth performance regardless of the YE supplementation or dietary protein levels. Growth performance of late finishing pigs (76~101 kg BW) was also not significantly different among treatments. However, ADG of pigs fed YE diet was significantly improved (p<0.05) regardless of the dietary protein levels. For the overall period (51~101 kg BW), although adding YE to the diet and elevating the protein level showed better ADG, there were no significant differences on growth performance among treatments. Early finishers showed significantly higher crude protein, crude ash and crude fat digestibilities when they were fed diets supplemented with YE. Digestibilities of amino acids were not affected by YE. Late finishers did not show any significant differences in proximate nutrient digestibilities regardless of YE supplementation or dietary protein levels. YE tended to slightly improve the CP digestibility, however no significant difference was found with increased dietary protein levels. There was no significant difference in amino acid digestibilities with YE supplementation or dietary CP levels during the late finishing period. Dry matter (DM) and nitrogen (N) excretion in feces did not show any significant difference among treatments. Early finishing pigs also did not respond to the inclusion of YE or dietary protein levels (p<0.05). Fecal N excretion of early finishing pigs seemed to be lowered in pigs fed YE. Pigs fed medium dietary protein diet tended to excrete a higher amount of N during the early finishing period, but not statistically different. A slight increase in fecal N excretion was found with the increased level of dietary protein during the late finishing period. For ammonia nitrogen excretion, although there was no significance, the NH3-N content tended to be increased by the increased dietary protein levels and with YE supplementation. The NH3-N content in manure increased by 24.5% with YE supplementation. There were no significant differences in carcass weight, backfat thickness, carcass grade and loin eye area among treatments. However, pigs fed non-YE with low protein diet showed a significantly (p<0.05) low carcass ratio among treatments and there was significant (p<0.05) difference between the YE-added treatment and non YE treatment in carcass ratio. As for the feed cost, the cost of feeding high level protein was higher than that of medium level protein by 5% and low level protein by 9% (p<0.05). Therefore, based on this study, it could be concluded that environmentally friendly agents might play a role to some extent in finishing pigs from the aspect of pollution control, and that more than 14 and 12% of dietary protein for early finishing and late finishing pigs respectively do not necessarily guarantee high growth performance.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.1
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• pp.1-7
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• 1997

This experiment was conducted with total 960 brown layers, consisted of 8 treatment to investigate the effects of dietary chromium as chromium picolinate on egg production, egg quality, nutrient utilizability, serum traits and mortality in brown layers. Layers were fed diets with two levels of dietary protein (14% and 16%) and supplemented with 0, 200, 400, 800 ppb/kg of chromium as chromium picolinate, respectively. The highest egg production, egg weight and egg mass were found in 800 ppb chromium picolinate supplementation group with high protein level (16%) (p < 0.05). Although there was no significant difference, layers receiving 400 ppb of chromium picolinate with high protein (16%) represented the lowest broken eggs. The utilization of energy, dry matter and crude protein of 400 ppb chromium picolinate group with low protein level (14%) were significantly higher than those of control or other chromium picolinate group (p < 0.05). 400 ppb chromium picolinate with low protein level (14%) showed the lowest serum glucose concentration. But serum glucose concentrations in all treatments showed no significant differences. Present date revealed that the lowest serum cholesterol concentration of layers was found at 400 ppb chromium picolinate group with high protein level (16%) (p < 0.05). Crude protein content in yolk was significantly higher in eggs of layers received 800 ppb chromium picolinate and the lowest in eggs from layers received 400 ppb chromium picolinate among chromium picolinate levels (p < 0.05). Mortality was remarkably decreased by chromium picolinate supplementation and the lowest mortality value was found in layres receiving 800 ppb chromium picolinate with high protein level.

• Korean Journal of Poultry Science
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• v.20 no.2
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• pp.73-92
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• 1993

This study was conducted to investigate the effect of dietary metabolizable energy and crude protein levels on the performance and abdominal fat pad of broiler chicks. A total of 702, a day-old chicks were alloted into nine groups differing in dietary metabolizable energy (2,800, 3,000 and 3, 200kcal/kg) and crude protein(16, 18 and 20%) level from July 10 to September 4, 1990 for 8 weeks. The results obtained were summarized as follows. 1. Body weight gain was significantly increased by increasing of metabolizable energy level (p＜0.05), but there was no significant difference between 2,800kcal/kg and 3,000kcal/kg, or 3,000 kcal/kg and 3,200kcal/kg of metabolizable energy, and there was no significant difference among crude protein levels. 2. Feed consumption tended to decrease by increasing of metabolizable energy and crude protein levels, but there was no significant difference among treatments. 3. Feed conversion was significantly improved by increasing of metabolizable energy level (p＜0.01), and it was showed a tendency to improve by increasing crude protein level(p＜0.05), but the difference between 18% and 20% of crude protein level was not significant. 4. Eviscerated yield was not different significantly among treatments. 5. Abdominal fat pad was significantly increased by increasing of metabolizable energy level (p＜0.01), but there was no significant difference between 2,800kcal/kg and 3,000kcal/kg, or 3,000kcal/kg and 3,200kcal/kg of metabolizable energy. On the other hand, abdominal fat pad in 20% of crude protein level was significantly lower than those in 16% and 18% of crude protein level (p＜0.01). 6. The feed cost per kilogram body weight gain tended to decrease by increasing of metabolizable energy level, and that in 18% of crude protein level was slightly lower than those in 16% and 20% of crude protein level, but there was no significant difference among treatments.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.4
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• pp.556-563
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• 2019

Objective: This experiment was conducted to investigate the effect of reducing dietary metabolic energy (ME) and crude protein (CP) levels on growth performance, blood profiles, and nutrient digestibility in weaning pigs. Methods: A total of 240 crossbred pigs ($Duroc{\times}[Landrace{\times}Yorkshire]$) with an average body weight of $8.67{\pm}1.13kg$ were used for a 6-week feeding trial. Experimental pigs were allotted to a $2{\times}3$ factorial arrangement using a randomized complete block design. The first factor was two levels of dietary ME density (low ME level, 13.40 MJ/kg or high ME level, 13.82 MJ/kg) and the second factor was three dietary CP levels based on subdivision of early and late weaning phases (low CP level, 19.7%/16.9%; middle CP level, 21.7%/18.9%; or high CP level, 23.7%/20.9%). Results: Over the entire experimental period, there were no significant difference in body weight among groups, but a decrease in diet energy level was associated with an increase in average daily feed intake (p = 0.02) and decrease in gain-feed ratio (G:F) ratio (p<0.01). Decreased CP levels in the diet were associated with a linear increase in average daily gain (p<0.05) and quadratic increase in G:F ratio (p<0.05). In the early weaning period, blood urea nitrogen concentration tended to increase when ME in the diet decreased and decrease when CP level in the diet decreased (p = 0.09, p<0.01, respectively). Total protein concentration tended to increase when CP level was reduced (p = 0.08). In the late weaning period, blood urea nitrogen concentration decreased linearly as CP level decreased (p<0.01). The CP and crude fat digestibility decreased when ME was decreased by 0.42 MJ/kg (p = 0.05, p = 0.01, respectively). The CP digestibility increased linearly as CP level decreased (p = 0.01). Conclusion: A weaning pig diet containing high ME level (13.82 MJ/kg) and low CP level (19.7%/16.9%) can improve pig growth performance and nutrient digestibility.

• Journal of Aquaculture
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• v.13 no.1
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• pp.1-7
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• 2000

The effect of various dietary protein levels on growth and body composition of young common carp raised from 56 g to 170 g in recirculating system was investigated for 15 weeks when they were fed to visual satiety three times daily. Five experiemtal diets were formulated to contain 40, 35, 30, 25 and 21% protein levels and 3.56, 3.59. 3.63, 3.66 and 3.69 kcal/g diet GE levels respectively. Mean survival rates of the fish fed the 40, 35, 30 and 25% protein diets were not different but sig-nificantly higher than that of the fish fed the 40, 35, 30 and 25% protein diets were not different but sig-nificantly higher than that of o the fish fed the 21% protein diet(P<0.05) Weight gain (g/tank) of common carp fed the 30% protein diet was the best. However weight gain of the fish fed the 25, 30, 35 and 40% protein diets were not different but significantly better than that of the fish fed the 21% protein diet. Feed efficiency ratio of the 21% protein diet was significantly lower (P<0.05) than for other groups of diets which were not different among them. Protein efficiency ratio for the 21% protein diet was significantly lower (P<0.05) than for other groups of diets which were not different among them(P>0.05) Dietary protein level had no effect on hemoglobin content in the fish(P>0.05) Crude protein contents of whole body of the fish fed the 35 and 40% protein diets were significantly higher than that of the fish fed the 21$$\mid$% or 25% protein diet(P<0.05) Body crude lipid contents of the fish fed the 21 and 25% protein diets were significantly higher than that of the fish fed the 30% or 35% protein diet. Crude ash contents of the fish fed the 35 and 40% protein diets were significantly higher than that of the fish fed the 21% or 25% protein diet(P<0.05) Moisture content of the fish fed the 35% protein diet was significantly higher than that of the fish fed the 21% protein diet(P<0.05) In considering growth performance of common carp and efficiency of diet dietary protein level could be lowered up to 25% without the reduction of young common carp production in recirculating system.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.4
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• pp.344-348
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• 2009

This study was conducted to investigate effects of dietary lipid level on growth and body composition of juvenile red sea bream in low temperatures. Duplicate groups of fish (initial body weight of 79 g) were fed one of three isonitronic diets (47% crude protein) containing different lipid levels (10%, 17% and 22%) for 25 weeks during the winter season. Weight gain and survival of fish fed 17% lipid diet were significantly (P<0.05) higher than those fish fed the 10% or 22% lipid diet. Protein efficiency ratio, daily feed intake, condition factor, hepatosomatic index and viscerasomatic index were not affected by dietary lipid level, but feed efficiency of fish fed 10% lipid diet was significantly (P<0.05) lower than those fish fed the 17% or 22% lipid diet. Proximate composition of the whole body, liver, viscera and dorsal muscle were not significantly different among all groups except for crude protein content of dorsal muscle. The contents of 16:0, 18:0, 20:4n-3 and 20:5n-3 of the whole body were significantly (P<0.05) affected by dietary lipid level. The results of this study suggest that an increased dietary lipid level from 10% to 17% can improve growth of juvenile red sea bream in low temperature periods.