Percent Of Diet Research Articles

Effect of nitrogen-sulfur ratio on the digestibility of roughage based diet incubated with rumen liquor of buffalo

In a compeletely randomized experiment, with factorial arrangment, the effects of three levels of urea and four levels of sulfur were tested on in vitro digestibilty and fermentability of rouphage based ration, incubated in rumen liqure of buffalo. Results showed that in vitro digestibility were not affected by the levels of urea, sulfur, or interaction of these factores. There was no variation among the treatments up to 12h of incubation for the cummulative gas production, but it was reduced when surful level increased from 0.37 to 0.41 or 0.45 percent of diet. Regardless of sulfur, urea significantly (p<0.05) affected gas production. There was also an interaction effect between nitrogen and sulfur levels on gas production, after 12 or 24h of fermentation (p<0.05) but not for the longer times of incubation. It could be concluded that 0.33% sulfur and 0.5 or 1.0% urea which provided a total N/S ratio of 4.68 to 5.28 or urea N/S ratio of 0.66 to 1.34 may be optimum ranges for rumen fermentations of rouphage based diets in buffalo.

Feeding Lactose Increases Ruminal Butyrate and Plasma β-hydroxybutyrate in Lactating Dairy Cows*,†

Ruminal fermentation of lactose increases molar proportions of butyrate, which is metabolized by the ruminal epithelium to β-hydroxybutyrate (BHBA). To determine the effects of dietary whey, and specifically lactose, on concentrations of ruminal and blood volatile fatty acids (VFA) and blood BHBA, 8 Holstein and 4 Brown Swiss multiparous cows (210±33 d in milk) were blocked by breed and randomly assigned to one of three 4×4 Latin squares. Treatments were control (CON; 7.1% of dietary dry matter [DM] as cornstarch), liquid whey (WHEY; 9.4% of diet DM) containing 70% lactose on a DM basis, low lactose (LOLAC; 7.1% lactose), or high lactose (HILAC; 14.3% lactose). Diets contained 53% forage as corn silage, alfalfa hay, and grass hay (DM basis) and a corn and soybean meal-based concentrate. Average dietary percentage of crude protein and energy density (Mcal/kg net energy for lactation) were 16.8 and 1.47, respectively. Feeding lactose increased DM intake. Milk production and composition were not affected by diet with the exception of decreased urea nitrogen in milk from cows fed lactose. Greater proportions of ruminal propionate were observed in cows fed CON relative to those fed WHEY and LOLAC. Increasing dietary lactose increased proportions of ruminal butyrate and decreased acetate and branched-chain VFA. Concurrent with the increase in ruminal butyrate concentrations, there was an increase in plasma BHBA as lactose in the diet increased. Concentrations of VFA in plasma were not affected by diet with the exception of the branched-chain VFA, which were increased in cows fed LOLAC compared with WHEY. These data indicate lactose fermentation increases proportions of ruminal butyrate and plasma BHBA in lactating dairy cows; however, the observed increase in plasma BHBA is not sufficient to subject cows to ketosis.

Impact of different dietary lipid sources on growth, lipid digestibility, tissue fatty acid composition and histology of rainbow trout, Oncorhynchus mykiss

The aim of the present study was to determine the impact of replacing at least 50% of the fish oil by alternative lipid sources in diets for rainbow trout on growth, lipid digestibility, fatty acid profiles of liver and muscle and tissue histology. Four experimental diets were formulated combining two fish oils (capelin and anchovy) with different vegetable oils (soybean, rapeseed, palm and olive) and one type of animal fat (lard), in order to obtain 60% to 80% fish oil replacement. A fifth diet prepared with pure fish oil (capelin oil) served as control. The diets were fed to apparent satiation twice a day to triplicate groups of 30 rainbow trout with an initial weight of 250 g for 64 days at 12 °C. Growth was good (TGC 3 3.7–3.9) and independent of diet. Final body weight was on average 760 g. Feed conversion ratios (FCR) ranged from 0.72 to 0.79. The only significant difference in FCR was found in the group fed an olive oil–lard combination replacing 80% of the fish oil. This diet also had a lower apparent lipid digestibility (79% vs. 91–94% for the rest of the diets). The liver and muscle fatty acid compositions were similar within groups and reflected that of the diets. But, tissue levels of 20:5 n−3 were lower and levels of 22:6 n−3 were higher than their respective dietary percentages. Histologically, a supranuclear accumulation of lipid droplets was observed in the intestinal cells of some of the groups fed diets supplemented with vegetable oils. Similarly, livers from these groups showed large amounts of lipid droplets within the hepatocytes. The present results suggest that most of the fish oil can be replaced by the alternative sources tested without compromising growth and feed utilisation. However, the histological changes observed suggest an impact of dietary lipid source on the transport and/or metabolism of fat in the fish. This requires further investigation.

Development and evaluation of new artificial diet for mass rearing Hypothenemus hampei ( Coleoptera: Scolytidae)

A new artificial diet called CENIBROCA (C) was developed for rearing coffee berry borer. It has fewer ingredients, good characteristics of nutrition to the target pest. good consistency keeps humidity longer, has low contamination, and is easy to prepare. Its reproductive potential and rate of increase were evaluated and compared with the following diets: Diet 140 (A), developed in Mexico in 1993; ECOBROVILL-160 (B), developed in Mexico in 1995, which is a simplification of the diet (A); and parchment coffee (D), the natural medium of rearing coffee berry borer used since 1989. Diets A, B, and C were poured into 50x10 mm glass tubes. Each tube contained 1 mi of diet and a recently emerged female. Parchment coffee was evaluated by individual infestation in the same way as an artificial diet. On evaluation after 40 days, diet Chad a mean production of 53,9 ± SD=6,3 insects per tube of diet, followed by diets Aand B with a mean production of 46,0 ± SD=6,1 and 40,1 ± SD=8,9 insects percent of diet respectively, the lowest production was for parchment coffee with 26,9 ± SD=5 insects of CBB. At 60 days, 254,6 ± SD=80,0 stages (50% were eggs, probably the third generation) were found on CENIBROCA, showing a significant difference (p&lt;0,05) in relation to the diets, 140 with a mean production of 125,8 ± 49,4 states and 107,5 ± 50,9 to ECOBROVILL, respectively. The highest reproductive rate ( R0 ) and the maximum values of the intrinsic rate of increase (rm) of CBB were found in artificial diet C.

Changes in hepatic branched-chain α-keto acid dehydrogenase activity in response to isoleucine imbalance in growing chickens

Three experiments were carried out to determine the influence of isoleucine imbalance on hepatic branched-chain α-keto acid dehydrogenase (BCKAD) activity in growing chickens. An isoleucine imbalance was induced by adding a 5% imbalancing amino acid mixture to a basal diet that contained adequate concentrations of all indispensable amino acids except isoleucine, which was marginally adequate (0.64–0.76% of the diet). The imbalancing mixture caused depressions ( P < 0.05) in feed intake and growth rate. The depression in feed intake appeared to occur prior to the depression in growth rate. The isoleucine concentration in plasma decreased ( P < 0.05), but not consistently, among experiments in response to the imbalancing mixture of amino acids. Basal and total activities of hepatic BCKAD were increased ( P < 0.05) 21% and 28%, respectively, within 24 hours in one experiment and were elevated ( P < 0.05) 19% and 14%, respectively, at the end of the 13 days of a second experiment. The moisture, protein, and fat contents of whole body and liver were not affected by the imbalancing mixture of amino acids. It appears likely that broiler chicks did not adapt to the imbalanced diets because the depressed feed intake and growth rate and alterations in plasma isoleucine and hepatic BCKAD activity persisted through 13 days of experiment. The isoleucine requirement, expressed as percent of diet, was increased by the imbalancing mixture of amino acids, and the efficiency of isoleucine utilization for growth (grams of weight gain per milligram of isoleucine intake) was decreased in two of three experiments. These results suggest that BCKAD may have a play in the increased isoleucine requirement of broiler chicks under conditions of isoleucine imbalance.

Influence of porcine somatotropin on the phosphorus requirement of finishing pigs: II. Carcass characteristics, tissue accretion rates, and chemical composition of the ham.

We investigated the effects of recombinant porcine somatotropin (pST) on the requirement for P to maximize lean tissue accretion and to minimize fat tissue accretion in two experiments using finishing pigs. Corn-soybean meal diets with varying levels of P were fed, and Ca was adjusted to maintain a Ca:P ratio of 1.1:1. In Exp. 1, 96 pigs were fed dietary P concentrations of .35, .45, and .65% from 75 to 109 kg BW. One-half of the pigs were injected daily with 4 mg of pST. Administration of pST increased (P < .05) percentages and accretion rates of lean tissue, bone, skin, water, and protein, but it reduced (P < .05) those of fat tissue and lipid. Increasing dietary P had little effect on chemical composition or accretion rates in untreated pigs, but it increased (P < .05) ash percentage and accretion in pigs treated with pST. Experiment 2 consisted of 66 pigs fed six dietary P concentrations (.35, .50, .65, .80, .95, and 1.10%) from 72 to 114 kg. One-half of the pigs were injected daily with 4 mg of pST. Percentages and accretion rates of lean tissue, bone, skin, water, and protein increased (P < .05) with pST, but those of fat tissue and lipid were reduced (P < .05). Increasing dietary P increased accretion rates of bone and skin (linear, P < .05), lean tissue, water, protein, and ash (quadratic, P <.05), and it reduced (quadratic, P < .05) that of lipid in pigs treated with pST. Dietary P level did not consistently affect percentages or accretion rates of tissues or chemical components in untreated pigs. In most instances, pigs treated with pST required higher dietary P levels and greater daily intakes of P to maximize lean tissue and protein deposition and to minimize fat tissue and lipid accretion than untreated pigs. These results indicate that finishing pigs treated with pST require higher dietary percentages of P to maximize carcass lean deposition as compared with untreated pigs.

Phosphorus Equivalence of Microbial Phytase in Turkey Diets as Influenced by Calcium to Phosphorus Ratios and Phosphorus Levels

Male day-old turkey poults (n = 768) were fed 0, 300, 600, or 900 U of phytase/kg of a corn-soybean diet in combination with four Ca:total P (tP) ratios of 1.1, 1.4, 1.7, and 2.0:1, and two levels of nonphytate P (nP) of 0.27 and 0.36% in a 21-d trial. Dietary Ca:tP ratios were obtained by varying defluorinated phosphate and limestone at the expense of cornstarch. The calculated dietary percentage of phytate P was 0.266 for all diets. Phytase additions linearly increased (P < 0.05) BW gain, feed intake, gain:feed, toe ash content, and apparent retentions of Ca and P at each Ca:tP ratio and nP level, but the response was influenced by dietary Ca:tP ratios and P levels. The detrimental effect (P < 0.02) of widening the Ca:tP ratio was observed for all measurements at each phytase and P level, and was greatest at lower phytase and P levels. Widening the Ca:tP ratio from 1.4 to 2.0 decreased the phytase efficacy by 7.4 and 4.9%, respectively, for 0.27 and 0.36% nP diets, which was close to the decrease in the phytase activity in vitro by 7.5 and 6.7%, respectively. The largest responses to supplemental phytase were achieved when poults were fed diets with 600 and 900 U of phytase/kg diet, respectively, for 0.36 and 0.27% nP, and for Ca:tP ratios ranging from 1.1 to 1.4:1. Second-order translog equations were generated for the phytase, Ca:tP ratio, and P effect, and nonlinear and linear equations for the phytase and Ca:tP ratio effect. Based on an assessment for the R2 and P values of equations, BW gain, feed intake, toe ash content, and P retention were sensitive measurements of the response to phytase addition. Equivalent equations were developed to determine the P equivalency of supplemental phytase. About 652 and 963 U of phytase were equivalent to 1 g nP, respectively, for 0.27 and 0.36% nP diets in turkey poults from hatch to 21 d of age.

Black Bear Habitat Use in Relation to Food Availability in the Interior Highlands of Arkansas

A black bear (Ursus americanus) food value index (FVI) was developed and calculated for forest cover type classifications on Ozark Mountain (White Rock) and Ouachita Mountain (Dry Creek) study areas in western Arkansas. FVIs are estimates of bear food production capabilities of the major forest cover types and were calculated using percent cover, mean fruit production scorings, and the dietary percentage of each major plant food species as variables. Goodness-of-fit analyses were used to determine use of forest cover types by 23 radio-collared female bears. Habitat selection by forest cover type was not detected on White Rock but was detected on Dry Creek. Use of habitats on Dry Creek appeared to be related to food production with the exception of regeneration areas, which were used less than expected but had a high FVI ranking. In general, pine cover types had low FVI rankings and were used less than expected by bears. Forest management implications are discussed. Int. Conf. Bear Res. and Manage. 9(1):309-318 Black bear populations in the eastern United States are much reduced, largely due to land conversion that resulted in habitat loss and fragmentation (Maehr 1984). Schoen (1990) stated that part of our task in managing bear habitats is to identify what habitats are important to bears and determine the optimal or sometimes minimal habitat mix necessary for maintaining populations at desired or viable population levels. Although food is only one component of an organism's habitat requirements, it is especially important for bears because of their large size and relatively inefficient digestive system (Pritchard and Robbins 1990). It is important to determine what foods are most critical to bears and the forest management practices that produce those foods. Although a number of habitat use studies have been conducted on black bears in North America (Beeman and Pelton 1977, Warburton 1984, Brody and Pelton 1989, Unsworth et al. 1989, Hellgren etal. 1991), few studies have attempted to link habitat use with food availability (Kansas and Raine 1990, Noyce and Coy 1990). It is not only important to determine the habitats that are selected for by bears, but it is perhaps more important to determine why those habitats are selected. The objective of this study was to quantify food production and relative value assoeiated with a variety of silvicultural practices and forest cover types and compare that to black bear habitat use for 2 study areas in the Interior Highlands of Arkansas. This study was funded under provisions of the Federal Aid in Wildlife Restoration Act (PittmanRobertson Act), administered by the Arkansas Game and Fish Commission. Additional funding was provided by the Ozark National Forest (NF), the Arkansas Cooperative Fish and Wildlife Research Unit, and Environmental Systems Company, Inc. C.J. Amlaner, P.S. Gipson, M.R. Pelton, and T.B. Wigley provided advice on study design and, along with D.L. Garshelis, R.L. Kirkpatrick, and T.E. Martin, helped edit earlier manuscripts. Special thanks go to graduate student S.G. Hayes and a number of technicians for their assistance in the field. Appreciation is also extended to W.F. Limp, J.A. Farley, and J.J. Lockhart from the Arkansas Archaeological Survey for their valuable assistance in using the Geographic Information System (GIS).

Current Nutrition Practice and Knowledge of Varsity Athletes

Surveys were given to 812 varsity athletes from randomly selected Division IA universities to obtain information regarding current nutritional knowledge and practice. The athletes were volunteers from eight men's and women's sports and were required to give oral consent prior to the administration of the questionnaire. The comparison of results from studies conducted in the early 1980s indicated that athletes are still not properly educated with respect to most nutritional issues. Most respondents (72 percent) believed athletes needed vitamin supplements and 76.6 percent believed that vitamins contributed to energy. The belief among athletes that protein supplements are necessary has escalated since the early 1980s along with the probability (p < 0.05) that more males than females use protein supplements. Fifty-one percent of the athletes in this study believed that protein provided the main source of energy in activity. The use of supplements containing selected amino acids was low. However, 69.1 percent of all athletes thought that amino acids contributed to muscle mass and strength. Most respondents displayed minimal knowledge of recommended dietary percentages of fat and protein. The ability of athletes to identify the main functions of vitamins, fat and protein remains low. Current knowledge of the functions of carbohydrates, however, has improved and showed a positive trend. It was recommended that sequential action be taken to provide new coaches with basic nutritional knowledge and that measures be taken to educate athletes.

Dietary Habits and Body Composition in Adolescent Female Runners

The present study was conducted to compare dietary intakes and percentage of body fat between adolescent female runners and sedentary adolescent females. Thirty white girls, aged 15-18 years, served as subjects. Twenty had run between 20 and 55 miles per week for the past 1-5 years. The ten controls had not exercised for at least the past year other than in physical education classes. Nutrient intake was analyzed from 3-day dietary records. Percentage of body fat was estimated using hydrostatic weighing and skinfold thicknesses measured at the right triceps and calf. No significant differences were found between the 20 runners and the 10 controls in intakes of energy, calcium, or iron. Although daily caloric intakes were not higher for the runners, the two groups differed in percentage of body fat; the mean value for the runners was significantly lower than the control group’s value. Both groups consumed greater than recommended percentages of fat and less than recommended percentages of carbohydrates. In addition, both calcium and iron consumptions were below recommended values. In summary, the female runners had typically poor American teenage diets. Overall, these athletes should be instructed to increase their total kilocalories, consume a greater percentage of carbohydrates, and select foods high in calcium and iron.

Nutritional Value of Fresh Gambel Oak Browse for Spanish Goats

Little information is available on the nutritional value of fresh browse for ruminants. This study examined the nutritive value of Gambel oak (Quercus gambelii Nutt.) for Spanish goats. Fresh Gambel oak browse was harvested at 2 phenological stages and mixed with chopped alfalfa hay to formulate 6 diets, varying in oak content. Diets included 95% juvenile oak/5% alfalfa (95J), 80% juvenile oak/20% alfalfa (80J), 65% juvenile oak/35% alfalfa (65J), 80% mature oak/20% alfalfa (80M), 40% mature oak/60% alfalfa (40M), and an alfalfa control (ALF). Diets were evaluated for goats using a series of digestion-balance trials, in a completely randomized design. Dry matter intake was highest (P < 0.01) for animals on diets with mature oak (80M-37.8, 40M-34.5 grams kg(-1) day(-1), and lowest on diets containing juvenile oak (95J-23.6, 80J-31.6, 65J-29.9 grams kg(-1) day(-1)). Digestibility of dry matter and cell wall components was lower (P < 0.01) for mature oak diets, and higher for juvenile oak diets. Digestibility coefficients for dry matter were as follows: (80M-57.8%, 40M-58.8%, 95J-68.6%, 80J-65.3%, 65J-66.3%. Digestibility coefficients for cell wall were: 80M-33.1%, 40M-37.4%, 95J-53.7%, 80J-45.8%, 65J-47.3%. All diets provided nitrogen and energy in excess of maintenance requirements, as reflected by weight gains for all animals in every trial. Fecal and urinary nitrogen losses did not appear to be related to tannin content of the diets, since juvenile oak diets resulted in reduced nitrogen outputs, presumably due to reduced nitrogen intakes for these diets. We conclude that Gambel oak, even juvenile material in high dietary percentages (95%), provides adequate nutrients and should be considered a valuable forage for goats in oakbrush habitats.

Protein digestibility in dog. Effect of the quantity and quality of dietary fat (virgin olive oil and sunflower oil)

Protein digestibility has been estimated in dog when fed on two similar diets except their lipid quality (virgin olive oil and sunflower oil) from weaning up to 6 months of life. Experiments were carried out at 60, 105 and 150 days of adaptation to either diet. In dog, age does not seem to affect the protein digestive and metabolic utilization when fed on a high lipid content diet. A higher dietary fat percentage led to an increase of the mentioned parameters which could be caused to a delayed gastric emptying due to fat. As far as the fat quality is concerned, an improved protein digestive and metabolic utilization was evidenced in adult animals fed on olive oil. On the other hand, the weight progress was normal in both experimental groups. These results suggest that olive oil may have beneficial effects on protein digestibility as compared to sunflower oil.

Effects of feeding restricted energy and elevated calcium and phosphorus during growth on gait characteristics of culled sows and those surviving three parities.

Crossbred gilts (n = 288) were weaned at 4 to 5 wk of age and retained through three parities. They were used to determine the effects of feeding restricted energy (ad libitum vs 75% ad libitum) and elevated calcium-phosphorus levels (100 vs 150% of the dietary percentage suggested by NRC, 1979) from weaning to 100 kg of body weight on subsequent sow gait characteristics obtained from 16-mm motion pictures. After 100 kg, all females were fed and managed similarly throughout breeding, gestation and lactation. At 50 and 100 kg body weight and 21 d after weaning, females were filmed from the side and rear as they walked on a treadmill (traveling at the rate of .90 cm/s with zero slope) using two 16-mm Arriflex cameras. Objective measurements were taken from the film by projecting it on a reverse screen. Visual appraisal of structural soundness were scored subjectively for each female at each time period. The front foot pastern angle was correlated positively with structural soundness scores, suggesting that sows with smaller angles (more sloping) were given more desirable soundness scores. Early dietary energy and Ca-P levels did not influence number of sows completing three parities or culled for various reasons, front and hind pastern angles, the angles at the hock and carpal joint or rear view measurements, but sows fed ad libitum to 100 kg had a larger frame size even after three parities. Sows that survived three parities tended to have larger body capacity (girth diameter and width across hams) and smaller front and bind pastern angles and angles of the carpal joint and hock at maximum flex than did culled sows. Structural soundness scores did not differ between culled and surviving sows.

Effect of a metal mixture in diet on the toxicokinetics and toxicity of cadmium, mercury and manganese in rats.

The purpose of this work was to determine whether a metal mixture added to diet influences the toxicokinetics and toxicity of some elements. The metal mixture (MM) used in these experiments was ash (slag) from a coal gasification plant. The effect of this mixture (5 percent in diet) on the toxicokinetic and on the acute or subchronic toxicity of Cd, Hg, Mn was determined in rats of different ages. Rats were exposed for five weeks in toxicokinetic and six weeks in acute toxicity experiments. Sucklings were exposed through their mothers, which received the MM in diet over the pregnancy and lactation period. In toxicokinetic studies, half of the animals additionally received Cd, Hg or Mn (100, 50 or 2000 ppm, respectively) in drinking water. In subchronic experiments, six-week-old albino rats of both sexes were given MM in the diet and Cd, Hg or Mn in drinking water for 16 weeks. In toxicokinetic studies, 115mCd, 203Hg or 54Mn were administered orally or intraperitoneally to mothers and pups. Exposure to MM had no effect on the absorption, retention and organ distribution of these elements determined six days after radioisotope administration. In acute toxicity studies, exposure to MM in diet had no effect on LD50 values obtained eight days after oral administration of Cd, Hg or Mn to rats of different ages. In subchronic experiments, the effect of individual metals (Cd, Hg or Mn) was similar in animals with and without simultaneous exposure to the metal mixture (only a slight potentiation of a few health-effect parameters of cadmium was noticed in some animals). It is concluded that oral exposure to MM in the diet had almost no effect on the toxicokinetics and toxicity of Cd, Hg and Mn. This could be explained by the low level or low bioavailability of elements from MM, by the metal-metal interaction within the mixture or by the choice of health effect indicators determined. These results are presented as one of the potential approaches for studying the health effect of a metal mixture as occurring in the environment.

Efficacy of Pancreatic Enzyme Supplementation in Children with Cystic Fibrosis

Two studies were performed in children with cystic fibrosis (CF) to compare the efficacy and tolerability of pancreatic enzymes prepared as enteric-coated microspheres with that of a conventional enzyme preparation. The parameters evaluated included the following: fecal fat excretion, coefficient of fat absorption, daily caloric intake, percent of diet as fats, proteins and carbohydrates, increase in height and weight, frequency and consistency of stools, palatability of the preparation, and patient compliance. The first study was an open randomized crossover trial of an enteric-coated microsphere preparation (Pancrease) versus conventional pancreatin given alone or with cimetidine. With Pancrease compared to conventional pancreatin, a significant improvement was observed in all the digestive parameters in addition to better patient compliance. In the second study, the response of a group of CF patients given Pancrease for at least 3 months (3-67 months) was retrospectively compared with the response to conventional pancreatin, which had been given to the same patients from 10 months to 8 years earlier. In comparison to conventional pancreatin, Pancrease provided better digestive efficacy and greater increases in the growth rate of teenage patients. With Pancrease, the number of daily dosage units is decreased even when fat intake is increased. No adverse reactions were seen with either of the enzyme preparations used in these studies.

Efficacy of Pancreatic Enzyme Supplementation in Children with Cystic Fibrosis

SummaryTwo studies were performed in children with cystic fibrosis (CF) to compare the efficacy and tolerability of pancreatic enzymes prepared as enteric‐coated microspheres with that of a conventional enzyme preparation. The parameters evaluated included the following: fecal fat excretion, coefficient of fat absorption, daily caloric intake, percent of diet as fats, proteins and carbohydrates, increase in height and weight, frequency and consistency of stools, palatability of the preparation, and patient compliance. The first study was an open randomized crossover trial of an enteric‐coated microsphere preparation (Pancrease) versus conventional pancreatin given alone or with cimetidine. With Pancrease compared to conventional pancreatin, a significant improvement was observed in all the digestive parameters in addition to better patient compliance. In the second study, the response of a group of CF patients given Pancrease for at least 3 months (3–67 months) was retrospectively compared with the response to conventional pancreatin, which had been given to the same patients from 10 months to 8 years earlier. In comparison to conventional pancreatin, Pancrease provided better digestive efficacy and greater increases in the growth rate of teenage patients. With Pancrease, the number of daily dosage units is decreased even when fat intake is increased. No adverse reactions were seen with either of the enzyme preparations used in these studies.

The effects of dietary amino acid levels upon lysine and methionine requirements for growing rats.

The amino acid requirement has been investigated by many laboratories since 1931. Authors considered that the requirement was influenced by the protein level of the basal diet and also by the experimental method. In light of those earlier studies, the present study investigated the effect on lysine and methionine requirements by modifying total nitrogen level or essential amino acid level. The result of our study confirmed that when the amino acid requirement for maximum growth was expressed as the dietary percentage, amino acid to total amino acid ratio, and amino acid to total nitrogen ratio, the requirement had changed according to not only essential amino acids but also to nonessential amino acids. Furthermore, we investigated the relationship between amino acid intake and body protein gain, and found that 6.2 mg lysine and 9.0 mg methionine were required for the maintenance of a rat weighing 80 g and 71.6 mg of lysine and 48.8 mg of methionine were required for one gram of body protein gain. The lysine and methionine intakes required for one gram of protein gain were equivalent to 100% and 124% of amino acid contents of body protein, respectively.

Threonine Requirement of the Broiler Chick as Affected by Protein Level and Source

The threonine requirement of the young broiler chick was estimated in two experiments. In Experiment 1, a threonine-deficient corn-peanut meal-amino acid mixture was included in a basal diet at levels equivalent to 15 and 20% crude protein. In Experiment 2, a purified crystalline amino acid mixture, also limiting in threonine, was included in a basal diet at levels equivalent to 10.98 and 18.3% crude protein. When expressed as a percent of diet, the estimated threonine requirements increased as dietary protein content increased. However, when expressed as a percent of dietary protein, the estimated threonine requirements were not significantly affected by dietary protein content, and were similar for the two experiments. It was concluded that the threonine requirement is 3.7% of dietary crude protein, and is little affected by dietary protein content.

Response of Rats to Diets of Equal Chemical Score: Effect of Lysine or Threonine as the Limiting Amino Acid and of an Amino Acid Excess

The effect of lysine or threonine deficiency with or without excesses of all other amino acids was evaluated in a 21-d feeding study with male rats. Four amino acid mixtures were designed to be first limiting for the rat in lysine or threonine and contained either 0 or 50% excess of nonlimiting amino acids. These mixtures were incorporated into purified diets to provide seven levels [20–140% of the National Research Council (NRC) requirement] of the limiting amino acid. Food intake, body weight gain and carcass composition were measured for each rat to determine the effects of the identity of the limiting amino acid and of amino acid excess on the response to dietary chemical score. Significant effects and/or interactions of the identity of the limiting amino acid (i.e., Lys or Thr) and the presence of excess amino acids were seen for each of the measured responses. At equivalent dietary percentages of the NRC requirement, threonine deficiency supported greater body weight gain than did lysine deficiency. At equivalent deficiencies (Lys vs. Thr) threonine-deficient rats were more susceptible to adverse effects of excess amino acids. When the limiting amino acids were incorporated into the diet through incremental addition of the deficient amino acid mixture, rats responded to levels of lysine or threonine in excess of the NRC requirement. These results suggest that the current NRC requirements for these amino acids are too low and that aspects of the dietary amino acid composition other than the percentage deficit of the limiting amino acid can be important determinants of animal response.

Threonine, histidine and lysine requirements of chum salmon fry.

Three 4-week feeding studies were conducted to determine quantitative requirements of chumsalmon fry for threonine, histidine and lysine. The basal diet containing crystalline L-amino acids and 5% casein as nitrogen sources (40% crude protein) were isonitrogenously supplemented with graded level of threonine, histidine and lysine by adjusting the level of alanine. Based on growth data, the requirements for threonine, histidine and lysine were found out to be 1.2, 0.7 and 1.9 percent of diet (dry weight basis), or 3.0, 1.6 and 4.8 percent of dietary protein, respectively.