• Asian-Australasian Journal of Animal Sciences
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• v.11 no.4
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• pp.351-362
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• 1998

Microbial growth efficiency in the rumen was studied in sheep given hourly, 31.25 g oaten chaff with either 0.31 and 0.88 g urea or 1.88 and 5.63 g casein (exp. 1) and 33.33 g oaten chaff with 1.04 casein or 0.3, 0.6 and 0.9 g urea or the mixture of the casein and urea (exp. 2). Concentrations of ruminal fluid ammonia increased with increasing nitrogenous supplements. Organic matter digestibility in sacco in the rumen was not different irrespective of N sources. Isoacids and valeric acid increased with increasing ingested casein but decreased with increasing urea intake. Peptide and amino acid pools in ruminal fluid increased with increasing ammonia concentrations (exp. 2) suggesting that proteolytic activity and transportation of peptides and amino acids across microbial membrane of rumen microbes may be regulated by the metabolite mechanism (intracellular amino acids and $NH_4{^+}$, respectively). Densities of total viable and cellulolytic bacteria in ruminal fluid increased with increasing ammonia levels but that of small Entodinia decreased. The density of fungal sporangia growth on oat leaf blades decreased with increasing ammonia concentrations but appeared to remain constant in the presence of casein. Efficiency of net microbial cell synthesis was 15-28% higher when ammonia concentrations increased from 100 to above 200 mg N/l regardless of N sources. In conclusion, supplementation of preformed protein had no effect on rumen digestion and microbial growth efficiency. This could not be accounted for its effect on ruminal fluid ammonia. Increased microbial growth efficiency with increasing ammonia levels may be due to a reduction in the turnover of microbial cells within the rumen.

• Journal of the Korean Home Economics Association
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• v.20 no.4
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• pp.91-98
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• 1982

Various kinds of legumes have included as essential foods in Korean diet. However, a little attention have been paid on variety of those beans other than soybean. Main purposes of this study is to evaluate the protein quality of raw and cooked, red mung bean. Eighty male, sprague-Dawely rats weighing 50 gram were devided into 16 groups, five rats each. Casein protein from red and mung bean were used was included to after true digestibility of the protein of legemes. After 4 weeks feeding period animals were sacrificed and following data: all determined food intake, body weight gain, F.E.R., pp.E.R. and weights of liver, kidney heart, spleen, testis, pancreas, skeletal muscles. Food intake, body weight gain, F.E.R., pp.E.R. of casein group were higher than those of experimental groups (red bean, mung bean) body weight gain was increased with protein increment in the diet in all groups. The weight of liver showed significant difference between standard group and experimental group. (red bean, mung bean) The nitro gen content of liver and muscles were increased with level of protein in the diets.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.1
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• pp.13-22
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• 1985

A study was undertaken to evaluate the nutritional quallity of protein from precooked seafoods. Procedures for evaluation included protein efficiency ratio(PER) using the rat, computed PER(C-PER) and discriminant computed PER(DC-PER) techniques. These procedures involve the determination of in vitro digestibility and amino acid composition of the sample prior to computation of C-PER and CD-PER value in laver was higher. For the oyster, the C-PER value was very close to the PER value obtained from the rat assay. The difference between DC-PER value and rat-PER or NPR was slightly lower than that between C-PER and rat-PER except oyster and laver. Seafood samples which posses a high in vitro protein digestibility may need the DC-PER procedure could offer more advantages in predicting the protein quality of seafood samples than the DC-PER procedure which showed poor in vitro digestibility.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.3
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• pp.219-226
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• 1986

To confirm the application of a newer in vitro assays to determining the nutritional value of marine crustaceans (mainly shrimps and crabs), which have been considered to be highly nutritive depending on their levels of the essential amino acids and digestibility, their C-PERs and DC-PERs were determined and studied the factors influencing their in vitro results. Four species of seawater shrimps and 2 species of seawater crabs were used in this experiment. The in vitro digestibilities showed $83{\sim}86\%$ for raw shrimps and the trypsin indigestibile substrate content (TIS) was ranged from 1.32 to 3.33 mg/g solid expressed quantitatively as mg of purified soybean trypsin inhibitor. The smaller size of shrimps revealed a greater in vitro digestibility and a lower contents of TIS. It was noted that the in vitro digestibility of raw blue crab meat was around $85\%$ while boiled tenner crab meat showed $86\%$ or above, and the leg meat had the greatest in vitro digestibility in the various parts of crab meats. The poor in vitro digestibilities for shrimp's and crab's meat, compared with that of the other seafoods as noted in previous reports, suggest that the drop in pH, due to the change in their freshness during harvesting and frozen storage, resulted in underestimating their digestibilities using four-enzyme digestion technique. The lysine contents in all samples were higher than that of ANRC casein but they contained a slightly lower sulfur-containing amino acids than those in ANRC casein. But the other EAA, such as valine, tyrosine and phenylalanine, were found to be a half as little as that in casein and played a key-factor in calculation of C-PER or DC-PER. It was observed that the value of C-PER and DC-PER for all samples ranged from 2.1 to 2.4, and the predicted digestibilities showed $90\%$ or above in all samples. It was a different results from the fact that the animal proteins bear a higher values and predicted digestibilities than those of C-PER values. The lack of correlation between C-PER and DC-PER values is attributable to the fact that the lower content of valine, tyrosine and phenylalanine, and drop in pH owing to the changes of freshness in marine crustacea proteins. Therefore, if a newer in vitro digestion technique-which are taken into account the pH drop before digestion, TIS content and released free amino acids and/or peptides-developed, C-PER assays can provide more advantages in assessing the protein nutritional value of marine crustacea than any other in vitro assays.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1116-1121
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• 1997

Effects of gamma irradiation onf the activity and the properties(amino acid compositions, in vitro digestibility and SDS-PAGE pattern) of proteolytic enzymes were investigated. The proteolytic activity of soluble human serine protease, enzyme in kiwi and pineapple decreased 10% and 30~65% by 5 kGy and 30 kGy, respectively. In dried pancreatin and lysozyme, the proteolytic and antimicrobial activities decreased 6~14% and 10~20% by 5kGy and 40kGy, respectively. The analysis of above 10kGy-irradiated soluble human serine protease by SDS-PAGE revealed radiolysis of the enzyme into protein or peptides of lower molecular weights. The irradiation of skim milk, hammastein casein, and lysozyme up to 40kGy had no deleterious effect on either the in vitro digestibility or amino acid compositions.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.6
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• pp.928-939
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• 2003

A study was carried out to determine the effect of de-hulling on apparent and true ileal amino acids digestibility of soybean meals for growing pigs. Twenty barrows (Duroc${\times}$Large white${\times}$Longer white) were fitted with a simple T-cannula at the distal ilium. Digestibility of 20 experimental diets was determined, nine of them were de-hulled soybean meal diets, and nine of them were regular soybean meal diets and two low protein casein diets for determination of endogenous amino acid correction for true digestibility determination. A TEX>$5<{\times}5<$ Latin Squares Design was adopted in this trail. The results showed that de-hulling increased apparent ileal digestibility of isoleucine, threonine, aspartic, tyrosine and indispensable and dispensable amino acid (p<0.05) in soybean meals. Furthermore, dehulling is also increased apparent digestibility of arginine, leucine, lysine, phenylalanine, alanine, glutamic acid, serine and gross amino acids (p<0.01). However, there were no significant differences found for histidine, methionine, tryptophan, cystine and glycine (p>0.05). Similar responses were found for true ileal digestibility. In three dehulled and non-dehulled pairs soybean meals from the same respective sources, de-hulling increased apparent digestibility of lysine, methionine, threonine and cystine 1.42%, 2.06%, 2.18% and 1.40% respectively. True digestibility of lysine, methionine, threonine and cystine was increased 1.65%, 1.94%, 2.30% and 1.82% respectively. A prediction equation for true ileal amino acid digestibility (including lysine and arginine) was established by multivariate linear regression. The independent variables included relevant amino acid, organic matter, crude protein, ether extract and nitrogen free extract. The coefficient R2 values of lysine and agrinine were 0.596 and 0.531 respectively. According to the crude protein content, a prediction equation for lysine and arginine content in soybean meal was also established by single linear regression. The coefficient $R^2$ values of lysine and agrinine were 0.636 and 0.636 respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.5
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• pp.477-484
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• 1986

The interaction of myofibrillar protein with lipid or oxidized lipid was considered to be mostly contributing to the drop of digestibility of fish meat products. The digestibility of myofibrillar protein was $92.11\%$ for flounder and $88.04\%$ for hairtail fish, repectively, and as a rule it decreased as both the amount of lipid and reaction time increased. It also decreased with increase in the amount of added linoleate and oxidized linoleate. However, when the reaction continued for 6 hours or more the digestibility rather increased, which was provably due to the unfolding of protein structure. The hot air dried hairtail fish showed the lowest C-PER values among all dried fish products. The protein quality of flounder, hairtail fish and their dried ones except hot air dried ones measured by C-PER procedure were superior to that of ANRC casein. DC-PER values of all samples were greater than those of C-PER values and the greater discrepancies were noted in hairtail fish (fatty fish) products which possessed the lower in vitro protein digestibilities. Predicted diegstibilities, which were calculated using amino acid profiles, of all samples except raw ones were overestimated in comparison with in vitro protein digestibilities. From the observations so far, formation of complex of lipids and protein was thought to be the most important factor in lowering protein digestibility of the dried fish meat products.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.9
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• pp.1326-1333
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• 2002

Studies were conducted with nine barrows, average initial body weight $44.5{\pm}2.1kg$, fitted with a T-cannula at the distal ileum, to determine the apparent ileal (and true) digestibility (AID and TID) of CP and AA in different cultivars of rapeseed meals and soybean meal. The barrows were fed either a casein diet or one of eight corn starch-based semipurified diets, formulated to contain 17.0% CP (DM basis) with one of seven different cultivars of rapeseed meal or soybean meal as the sole source of dietary protein, according to a six-period, nine-treatment, incomplete Latin Square. Chromic oxide (0.5%) was used as a digestibility marker. The pigs were fed of 4% of body weight twice daily, at 08:00 and 20:00 h. Ileal digesta were collected at 2 h intervals daily from 5 d to 7 d. The AID or TID values of CP and most AA (Cysteine excluded) were significantly lower in the rapeseed meals than in soybean meal (p<0.05). There were significant differences in the AID or TID values of CP and AA among the seven different cultivars rapeseed meals (p<0.05); the seven rapeseed meals were arranged according to the size of the AA digestibility values of the rapeseed meals from the greatest to the least, as Zayou 59, Youyan 7, Ganyou 16, Qingyou 2, Huaza 3, Ningza 1 and Lianglou 586; differences in CP, AA, NDF and ADF contents in the rapeseed meals were mainly responsible for the variation in the AID or TID values of AA among rapeseed meals. The AID value of CP can be used as an index of the AID or TID values of most AA in rapeseed meals. However, the AID value of CP was less appropriate as a direct indicator of the AID or TID values for cysteine, methionine, tryptophan, phenylalanine and proline.

• Journal of the Korean Home Economics Association
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• v.20 no.2
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• pp.91-102
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• 1982

This study was designed to find out the nutritional defect of general Korean diet and the effective way of nutritional supplementation. Seventy weanling Sprague-Dawley male rats weighing 51.8$\pm$0.9g were blocked into ten groups and fed ten different diets ad libitum for eight weeks: Standard groups(st gp) was given 72% sugar-20% casein diet: Cereal-vegetable group(c-v gp) was fed cereal-vegetable diet(c-v diet) composed of rice, barley, soybean, spinach and cabbage: the other eight groups were fed c-v diets supplemented with casein, vitamin $B_{2}$, calcium, vitamin A, vitamin B2 and A, vitamin A and calcium, vitamin $B_{2}$ and calcium, vitamin A and $B_{2}$and calcium, respectively, on the basis of each nutrients content of standard diet. The results were as follows: 1. Food intakes and body weight gains in all the experimental groups were significantly lower than st gp. Among experimental groups, casein gp and vit B2 gp tended to gain more body weights than c-v gp. 2. Through all the experimental period, F.E.R., pp.E.R., and NDPcal% did nod show significant differences among all the experimental groups and st gp. 3. The weights of liver, kidney, and gastrocnemius were significantly lower in all the experimental groups as compared with st gp. But brain and sex organ weights did not show differences among all the groups. 4. Nitrogen contents of total carcass, liver, and gastrocnemius in all the experimental groups tended to be increased as compared with st gp, and among experimental groups, they tended to be increased by casein supplementation and decreased by ca supplementation. 5. Apparent nitrogen digestibility, urinary and fecal nitrogen excretion, the amount of nitrogen retained, and N.P.U. did not show any significant differences among all the groups. 6. Serum total protein concentrations did not show any significant differences among all the groups.

• Food Science of Animal Resources
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• v.41 no.5
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• pp.855-868
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• 2021

The present study was designed to investigate the effects of protein formula with different casein (C) to whey protein (W) ratios on dispersion stability, protein quality and body composition in rats. Modification of the casein to whey protein (CW) ratio affected the extent of protein aggregation, and heated CW-2:8 showed a significantly increased larger particle (>100 ㎛) size distribution. The largest protein aggregates were formed by whey protein self-aggregation. There were no significant differences in protein aggregation when the CW ratios changed from 10:0 to 5:5. Based on the protein quality assessment (CW-10:0, CW-8:2, CW-5:5, and CW-2:8) for four weeks, CW-10:0 showed a significantly higher feed intake (p<0.05), but the high proportion of whey protein in the diet (CW-5:5 and CW-2:8) increased the feed efficiency ratio, protein efficiency ratio, and net protein ratio compared to other groups. Similarly, CW-2:8 showed greater true digestibility compared to other groups. No significant differences in fat mass and lean mass analyzed by dual-energy x-ray absorptiometry were observed. A significant difference was found in the bone mineral density between the CW-10:0 and CW-2:8 groups (p<0.05), but no difference was observed among the other groups. Based on the results, CW-5:5 improved protein quality without causing protein instability problems in the dispersion.