The effect of methionine supplementation on the levels of pancreatopeptidase E, trypsin, chymotrypsin and amylase in the pancreas of chicks receiving raw and heated soya-bean diets

Effect of Methionine Deficiency on the Growth Performance, Serum Amino Acids Concentrations, Gut Microbiota and Subsequent Laying Performance of Layer Chicks

This study was conducted to investigate the effect of methionine (Met) deficiency in the rearing period on the growth performance, amino acids metabolism, intestinal development and gut microbiome of egg-laying chicks and the continuous effects on the performance, egg quality, and serum amino acids metabolism of the subsequent development process. Three hundred sixty one-day-old chicks were randomly divided into two groups and fed on a basal diet (NC group, Met 0.46%) and Met deficiency diet (Met- group, Met 0.27%). Each group included six replicates with 30 chicks per replicate. The trial lasted 6 weeks (0–6 weeks), both groups were fed the same basal diet which met the needs of Met during the observation period (7–24 weeks). Results showed that Met deficiency significantly decreased (P < 0.05) body weight (BW), average daily weight gain (ADG), average daily feed intake (ADFI) and tibia length (TL) compared to the NC group during the trial period (0–6 weeks). Also, Met deficiency dramatically increased (P < 0.05) feed conversion ratio (FCR) during the trial and observation period (7–24 weeks). In addition, during the observation period, the BW and ADG were decreased (P < 0.05) in the Met- group. Moreover, Met- group decreased (P < 0.05) villi height and villi height/crypt depth ratio in jejunum at 6th weeks. In addition, the concentrations of serum main free amino acids (FAA) in the Met- group were significantly increased (P < 0.05) at 6th weeks, while were decreased at 16th weeks. Based on the α-diversity and PCoA analysis in β-diversity, there were no significant differences in the cecal microbial composition between NC and Met- groups. However, the LEfSe analysis revealed that differential genera were enriched in the NC or Met- groups. The Haugh unit, shell thickness and egg production in the Met- group were significantly lower (P < 0.05) than in the NC group. In conclusion, these results revealed that dietary supplementation of appropriate Met could substantially improve the growth performance, host amino acid metabolism and intestinal development and continuously improve the laying performance and thus boost the health of growing hens.

Effects of Microencapsulated Methionine on Milk Production and Manure Nitrogen Excretions of Lactating Dairy Cows

Simple Summary

Methionine (Met) deficiency in the diet can limit milk protein production and lead to excessive nitrogen (N) excretions to the environment by dairy cows. We demonstrated that the supplementation of a new rumen-protected Met product to a Met deficient diet increased milk protein yield and decreased manure N excretions of high producing dairy cows. Increased blood flow to the mammary glands and increased apparent total tract digestibility of dietary crude protein seem to be the underlying mechanisms for those improvements in production and the environmental sustainability.

Abstract

The study objective was to determine the effects of rumen-protected methionine (Met) by microencapsulation (RPM) on amino acid (AA) supply to the udder, milk production, and manure nitrogen (N) losses of dairy cows. A corn and soybean-based diet deficient in metabolizable Met (~10 g/d) was supplemented with RPM providing 0, 11.0, 19.3, and 27.5 g/d of Met. Dry matter intake (DMI), milk production, plasma essential AA (EAA), mammary plasma flow (MPF), and fecal (FN) and urinary N (UN) outputs (g/d) were determined. The RPM increased linearly milk yield, milk protein yield, and energy corrected milk yield (p < 0.040) without affecting DMI. Milk protein yield increased by 50 g/d for the 19.3 vs. 0 g/d dose (p = 0.006) but the rate of increment decreased for 27.5 g/d dose. Plasma Met, and MPF increased linearly with RPM dose (p < 0.050). Apparent total tract digestibility of crude protein (p = 0.020) and FN (p = 0.081) decreased linearly with RPM. The UN did not change but total manure N decreased linearly with RPM (p = 0.054). The RPM (19.3 g/d) seemed to help cows overcome the metabolizable Met deficiency while mitigating manure N excretions to the environment.

The effect of characteristics of proteins fed during gestation and lactation on development of metabolic syndrome in dams and male offspring of Wistar rats

Objective

The objective of the study is to examine the role of characteristics of proteins in maternal and weaning diets on risk of metabolic syndrome in male offspring.

Methods

Pregnant Wistar rats were allocated to two groups (n = 12) and were fed the AIN‐93G diets based on either intact protein‐based diet (IPD) or mixed amino acid‐based diet (AAD) from day 3 of gestation throughout gestation and lactation. Male offspring were weaned to either an IPD or AAD diet for 18 weeks.

Results

In dams, AAD group had lower body weight in post‐partum period and higher pulse rate compared with IPD group. In pups born to AAD dams, birth weight and body weight were significantly lower, and systolic blood pressure and fasting blood glucose were significantly higher compared with those born to IPD dams. Fat/weight ratio, insulin and homeostasis model assessment of insulin resistance were not influenced by either maternal or weaning diet.

Conclusions

These results indicate that the physico‐chemical structure of proteins fed to dams is important in altering risk factors of metabolic syndrome in the offspring, while weaning diets do not seem to play a role. IPD had more favourable effect than AAD. These results may also indicate that dietary recommendations during development must be updated based on physiological properties of dietary proteins that are beyond their nutritional role.

Dietary proteins as determinants of metabolic and physiologic functions of the gastrointestinal tract

Dietary proteins elicit a wide range of nutritional and biological functions. Beyond their nutritional role as the source of amino acids for protein synthesis, they are instrumental in the regulation of food intake, glucose and lipid metabolism, blood pressure, bone metabolism and immune function. The interaction of dietary proteins and their products of digestion with the regulatory functions of the gastrointestinal (GI) tract plays a dominant role in determining the physiological properties of proteins. The site of interaction is widespread, from the oral cavity to the colon. The characteristics of proteins that influence their interaction with the GI tract in a source-dependent manner include their physico-chemical properties, their amino acid composition and sequence, their bioactive peptides, their digestion kinetics and also the non-protein bioactive components conjugated with them. Within the GI tract, these products affect several regulatory functions by interacting with receptors releasing hormones, affecting stomach emptying and GI transport and absorption, transmitting neural signals to the brain, and modifying the microflora. This review discusses the interaction of dietary proteins during digestion and absorption with the physiological and metabolic functions of the GI tract, and illustrates the importance of this interaction in the regulation of amino acid, glucose, lipid metabolism, and food intake.

Pathological evaluation, clinical chemistry and plasma cholecystokinin in neonatal and young miniature swine fed soy trypsin inhibitor from 1 to 39 weeks of age

The potential toxicity of dietary soy trypsin inhibitor (TI) was evaluated in neonatal miniature swine. From 1 to 6 weeks of age, two groups of male piglets were artificially reared in an Autosow and automatically fed either TI or control liquid diet. From 6 to 39 weeks of age, these two groups were fed either TI or control chow diet. A third group, sow control (SC), suckled from birth to 6 weeks of age, were also weaned to control chow from 6 to 39 weeks of age. Clinical chemistry and plasma cholecystokinin (CCK) determined at 6, 18, 30 and 39 weeks of age, and serum amylase activity with gross and histopathological analyses of major organs at 6 and 39 weeks of age are reported. TI had no effect on plasma CCK, serum amylase activity, or numerous clinical chemistry values. TI-fed piglets had a larger relative liver weight at 6 weeks of age. Relative pancreas weight decreased with age but was not affected by TI. Gross and histopathological analyses of major organs, except the spleen, were within normal limits. Increased incidence of extramedullary hematopoiesis was noted in the spleen of the TI group at 6 but not at 39 weeks of age. There was no consistent pattern in immunohistochemical foci for secretin, gastrin releasing polypeptide or CCK, and no change in DNA, RNA, mitotic index or nuclear density of pancreatic cells. At 6 weeks of age, TI increased pancreatic protein and amylase activity but not trypsin or chymotrypsin activity. None of the effects suggested that this dose of TI was toxic to either the neonatal or sexually mature miniature male swine.

Pancreatic response in rats and mice to trypsin inhibitors from soy and potato after short- and long-term dietary exposure

The effects on the pancreas of chronic (95 wk) dietary exposure to protease inhibitors from soy and potato were compared in rats and mice. Soy and potato trypsin inhibitor (TI) concentrates were prepared from defatted raw soy flour and potato juice, respectively, by selective precipitation and ultrafiltration. Animals were fed a diet in which casein supplied approximately 20% protein. Each concentrate (less than 1% of the diet) was added to provide 100 and 200 mg of trypsin inhibitor activity per 100 g of diet. In short-term (28 d) experiments in rats, both sources of TI decreased the apparent nutritional quality of casein and produced pancreatic hypertrophy consistent with a hormonally mediated feedback mechanism for pancreatic adaptation to diet that is interactive with the nutritional status of the animal. After long-term feeding (95 wk), soy and potato TI produced dose-related pancreatic pathology in rats consisting of nodular hyperplasia and acinar adenoma, which was typical of that associated with raw soy flour. Although mice responded similarly to rats to soy TI in short-term (28-d) feeding experiments, they were resistant to the formation of these lesions following long-term feeding. This considerable species variation in propensity to develop preneoplastic and neoplastic lesions of the pancreas is not predicted by the short-term hypertrophic and hyperplastic response of the pancreas to TI.

Effect of dietary green gram trypsin inhibitor and raw green gram meal (Phaseolus aureus Roxb) on the pancreatic activity in rats

To evaluate the effect of green gram trypsin inhibitor (GGTI) and raw green gram meal (RGG) the experimental animals were fed with the following diets: (i) AGG meal-control (autoclaved green gram meal), (ii) RGG meal and (iii) AGG meal + 1% GGTI. Pancreatic enlargement was observed in rats fed RGG diet and AGG + GGTI diet. Elevated levels of protease and amylase were observed in pancreas. Intestinal contents showed no significant variation in the protease activity, but a significant variation in the amylase activity was evident. Total RNA, DNA and protein content were increased in the pancreas of group II and group III set of animals, suggesting an active proliferation of acinar cells. RNA and DNA content per unit weight of pancreas and the RNA/DNA ratio remained almost constant indicating the hyperplasia. Histological studies revealed hyperplasia of the acinar cells. The results obtained have been discussed.

The effect of dietary raw and autoclaved soya-bean protein fractions on growth, pancreatic enlargement and pancreatic enzymes in rats

1. Raw soya-bean meal (RS) was fractionated into soya-bean lyophilized extract (SLE), soya-bean lyophilized residue (SLR), acid-precipitated proteins (APP) and whey proteins. 2. Trypsin (EC 3. 4. 21. 4)and chymotrypsin (EC 3. 4. 21.1) inhibitors (TI) were soluble at pH 8 and remained soluble after the extract was acidified to pH 4.4 Except for whey, heating abolished, almost totally, their inhibiting activity. 3. Feeding SLE diet (high TI content) and APP diet (low TI content) resulted in growth depression below the RS level. Feeding the SLR diet resulted in an optimal growth. Feeding diets containing heated fractions improved the growth rate though not to the level observed with heated RS (HS) diet. 4. RS, SLE, APP and whey diets produced similar pancreatic enlargement which could be totally (RS, whey) or partially (SLE, APP) abolished by heating. 5. Feeding the RS diet reduced pancreatic amylase content. The factor responsible for this effect cofractionated with SLE and whey proteins. 6. Two groups of factors in the various diets were probably responsible for the elevation in pancreatic proteases. The first group were the heat-labile factors present in RS, SLE and whey whereas the second group resisted the heat treatment and were found in APP and SLR. 7. The results suggest that for optimal growth rate of rats, heat treatment should be given to the unfractionated soya-bean proteins rather than to the isolated fractions. The results further indicated that TI are not the only factors that can lead to pancreatic enlargement and changes in pancreatic enzymes composition.

Kinetics of native and modified Bowman-Birk soya-bean trypsin inhibitor on growth and enzymes activities of the chick pancreas

1. The Bowman-Birk soya-bean trypsin inhibitor (BBTI) begins to cause pancreatic enlargement and increased enzymic activity in the pancreas of chicks after a minimum of 7 d of feeding. 2. The active inhibitory site of BBTI against trypsin is the factor involved in the pancreatic enlargement and increase of pancreatic enzyme activity in chicks.

Enzymic activities in the pancreas, digestive tract and feces of rats fed raw or heated soy flour

Trypsin, chymotrypsin and amylase levels were determined in the pancreas, all along the intestinal tract, and in the feces of rats fed raw or heated soy flour diets. The levels of all enzymes measured in the pancreas in the non-fasted state were lower in the raw than in the heated soy flour-fed rats. Fasting equalized these levels. Trypsin and amylase tended to be lower, and chymotrypsin was significantly higher in the intestinal tracts of raw soy flour-fed rats than in the group fed heated soy flour; the greatest differences were found in the ileum. Trypsin and chymotrypsin levels in the feces were higher in the group fed raw soy flour than in the group fed heated soy flour. Amylase in the feces of the raw soy flour-fed rats was higher at the beginning of the experiment and dropped sharply to be even lower than in the heated soy flour-fed rats at days 13 to 14 of the experiment. It was concluded that measuring the enzymic levels in the feces is a very sensitive method for determining whether a test diet induces hypersecretion of digestive enzymes in rats. This method can be used from the start of feeding the experimental diet. As the animal need not be killed, the effect of the test diet upon enzymic secretion can be studied as a function of time, and it might be suitable to studies with large animals.

The effects of force-feeding on enzymes of the liver, kidney, pancreas and digestive tract of chicks

1. Force-feeding of young chicks for 15 d increased kidney arginase (EC3·5·3·1) activity threefold. Fasting for 30 h decreased this activity by 50%.

2. Liver xanthine dehydrogenase was slightly increased after force-feeding and decreased following fasting.

3. The specific activities of two pentose-phosphate-cycle enzymes were not significantly affected by force-feeding, but glucose-6-phosphate dehydrogenase (EC1.1.1.49) decreased following fasting.

4. The over-all secretion of digestive enzymes increased parallel to the increase in food consumption. Therefore, despite an increased absolute weight of the pancreas and intestinal chyme, specific activities were the same in the force-fed andad lib.-fed groups, except for a higher activity in intestinal amylase.

5. Fasting did not affect the pancreatic enzymic activities.