Comparison of the kinetics of pancreatic secretion and gut regulatory peptides in the plasma of preruminant calves fed milk or soybean protein

Desenvolvimento de bezerros leiteiros alimentados com silagem de leite de transição: I - Trato digestivo

Avaliou-se o desenvolvimento do trato digestivo de bezerros Holandeses aleitados com silagem de leite de transição. Foram utilizados 18 animais, com peso corporal inicial médio de 36,50kg (±4,03), alimentados individualmente em baias com concentrado, feno de Cynodon sp., água e suplemento mineral oferecidos ad libitum. O delineamento experimental foi inteiramente ao acaso, com três tratamentos e seis repetições. Os tratamentos consistiram em leite integral e silagem de leite de transição diluída em água ou misturada em leite, correspondendo a quatro litros diários divididos em duas refeições, durante 59 dias. Aos 60 dias, os bezerros foram abatidos e realizaram-se pesagens do trato digestivo e medidas histológicas das papilas ruminais. O sistema de aleitamento não interferiu nos consumos de concentrado e matéria seca total e no desenvolvimento de papilas ruminais (P>0,05). A silagem de leite de transição diluída em água resultou em menor peso corporal, menor peso corporal vazio e absoluto do abomaso e maior desenvolvimento intestinal. O aleitamento com silagem misturada em leite não comprometeu o desenvolvimento corporal e do trato digestivo até 60 dias de idade, representando alternativa ao aleitamento com leite.

Gastrin, cholecystokinin and gastrointestinal tract functions in mammals

The aim of the present review is to synthesise and summarise our recent knowledge on the involvement of cholecystokinin (CCK) and gastrin peptides and their receptors in the control of digestive functions and more generally their role in the field of nutrition in mammals. First, we examined the release of these peptides from the gut, focusing on their molecular forms, the factors regulating their release and the signalling pathways mediating their effects. Second, general physiological effects of CCK and gastrin peptides are described with regard to their specific receptors and the role of CCK on vagal mucosal afferent nerve activities. Local effects of CCK and gastrin in the gut are also reported, including gut development, gastrointestinal motility and control of pancreatic functions through vagal afferent pathways, including NO. Third, some examples of the intervention of the CCK and gastrin peptides are exposed in diseases, taking into account intervention of the classical receptor subtypes (CCK1 and CCK2 receptors) and their heterodimerisation as well as CCK-C receptor subtype. Finally, applications and future challenges are suggested in the nutritional field (performances) and in therapy with regards to the molecular forms or in relation with the type of receptor as well as new techniques to be utilised in detection or in therapy of disease. In conclusion, the present review underlines recent developments in this field: CCK and gastrin peptides and their receptors are the key factor of nutritional aspects; a better understanding of the mechanisms involved may increase the efficiency of the nutritional functions and the treatment of abnormalities under pathological conditions.

Defatted bovine colostrum-supplemented diet around weaning improves exocrine pancreatic secretion by means of volume, digestive enzymes, and antibacterial activity

OBJECTIVES

Exocrine pancreatic secretion contributes to limit pathogenic bacteria-associated diarrhea. Bovine colostrum, used in the treatment of diarrhea, reduces symptoms originating from gut pathogenic bacteria overgrowth. We hypothesized that bovine colostrum may stimulate the exocrine pancreatic secretion.

METHODS

Eighteen piglets fitted with 2 permanent catheters (for pancreatic juice collection and reintroduction) were allocated to 1 of the following 2 dietary treatments for 5 days: a control diet or a diet supplemented with defatted bovine colostrum. Pancreatic juice was collected daily, and digestive enzyme activities and antibacterial activity were determined.

RESULTS

The prandial pancreatic juice outflow, the basal and prandial lipase output, and the basal secretion of the antibacterial activity were, respectively, 60% (P = 0.08), 154% (P = 0.08), 92% (P = 0.06), and 72% (P < 0.05) higher in piglets fed a diet supplemented with defatted bovine colostrum.

CONCLUSIONS

With defatted bovine colostrum, the increased antibacterial activity secretion against Escherichia coli may limit pathogenic bacteria overgrowth of the gut and reduce diarrheal episodes. The role of secretin in the increased pancreatic juice flow and lipase secretion was considered.

Exocrine pancreatic secretion in pigs fed sow's milk and milk replacer, and its relationship to growth performance

The objective of this study was to quantify and compare the effects of sow's milk and 2 milk replacer diets (containing clotting or non-clotting protein sources) on exocrine pancreatic secretion, plasma cholecystokinin, and immunoreactive cationic trypsin in pigs. In addition, the relationship between exocrine pancreatic secretion and growth in milk-fed pigs was studied. In a changeover experiment, 9 chronically catheterized pigs of 6.6 +/- 0.19 kg of BW were studied for 3 wk. Pigs were assigned to each of 3 diets. Exocrine pancreatic secretion was measured from the third to the seventh day on each diet. The protein content and trypsin activity of the pancreatic juice were measured. Blood samples were taken at 10 min before and after milk ingestion and were analyzed for cholecystokinin and immunoreactive cationic trypsin. Pancreatic protein and trypsin secretion did not differ between pigs fed sow's milk and those fed milk replacer, but the volume secreted was less for the pigs fed sow's milk (0.75 vs. 1.03 mL x kg(-1) x h(-1); P < 0.01). A postprandial response to milk intake was not observed. The 2 milk replacer diets did not affect exocrine pancreatic secretion differently. The average exocrine pancreatic secretion (volume, 0.94 mL x kg(-1) x h(-1); protein, 4.28 mg x kg(-1) x h(-1); trypsin, 1.65 U x kg(-1) x h(-1)) was intermediate between literature values for suckling and weaned pigs. Plasma cholecystokinin was elevated (approximately 18 pmol x L(-1)) and showed low correlations with the pancreatic secretion traits. Plasma immunoreactive cationic trypsin was not significantly related to any of the pancreatic secretion traits and should therefore not be used as an indicator for exocrine pancreatic function in milk-fed pigs. Exocrine pancreatic secretion varied substantially among individual pigs (protein, 0.22 to 13.98 mg x kg(-1) x h(-1)). Pancreatic protein and trypsin secretion showed a positive, nonlinear relationship with performance traits. It was concluded that neither specific sow's milk ingredients nor the protein source are responsible for a low pancreatic protein secretion in suckling pigs. Exocrine pancreatic secretion was positively correlated with ADG in pigs at an identical milk intake.

Desempenho de bezerros alimentados com dietas líquidas à base de leite integral ou soro de leite

Quinze bezerros da raça Holandesa, desaleitados aos 30 dias de idade, foram utilizados para avaliar os efeitos da inclusão de fontes protéicas alternativas, em substituição às proteínas do leite integral, na formulação de sucedâneos do leite. Os animais foram divididos em três grupos: o grupo controle (C) - recebeu leite em pó integral reconstituído; o grupo sucedâneo SL (soro/leite) recebeu 41,6% da proteína bruta (PB) vinda do concentrado protéico de soro (CPS), 23,1% do soro de leite e 35,3% do leite em pó integral; e o grupo sucedâneo S (soro) recebeu 68% da PB vinda do CPS e 32% do soro de leite. O consumo de concentrado, feno, sal mineral e água foi mensurado diariamente, enquanto o ganho de peso foi avaliado semanalmente. Não houve diferença (P>0,05) para o consumo de concentrado, sal mineral e água entre os grupos, nos períodos avaliados. O consumo de feno e o ganho de peso foram inferiores nos animais do grupo S (P<0,05). A substituição de 100% do leite integral por CPS e soro de leite influenciou negativamente o desempenho.

Soybean: feed quality and safety. Part 2: pathology of soybean feeding in animals. A review

Various animal models in farm and laboratory animals indicate the possible pathological effect of soybean feeding. Immunity and tolerance to oral soybean intake and a generalised meta-model of effects are discussed. It seems that FAO/WHO recommendations will have to be considered in assessing the biological value of soybean feed sources. Determination of hull content, antigenic potential, conglycinin and trypsin inhibitor content is warranted in view of the future component pricing of soybean meals.

Presence and localization of CCK receptor subtypes in calf pancreas

This study was undertaken to confirm the presence of CCK receptor subtypes in calf pancreas and establish their cellular localization. Using specific antibodies against CCKA and CCKB receptors, somatostatin, glucagon and insulin, we were able to confirm by Western blot the presence of both CCK receptor protein subtypes in the calf pancreas as a 80-85-kDa CCKA receptor and 40-45-kDa CCKB receptor. By immunofluorescence, the CCKB receptor colocalizes with the islets' somatostatin delta cells, confirming what was previously shown in other species, as well as on ductal cells. We could not reproduce in the calf its colocalization with glucagon alpha cells as observed in human and rat. Any specific localization of CCKA receptors with our multiple antibodies failed. Our observation that the CCKB receptor subtype is specifically localized on pancreatic delta cells as well as on ductal cells lets us support the hypothesis that in this species, CCK could be involved in somatostatin metabolism as well as hydrelatic secretion; its effect on enzyme secretion would be indirect.

The effects of α-lactabumin and whey protein concentrate on dry matter recovery, TCA soluble protein levels, and peptide distribution in the rat gastrointestinal tract

The effects of two dietary proteins on dry matter recovery, trichloroacetic acid (TCA) soluble protein concentration, and peptide distribution in gastrointestinal contents were investigated in rats trained to consume, in a single 2-hour daily meal, diets containing α-lactalbumin (α-LA) or whey protein concentrate (WPC) for two weeks. Compared with the WPC diet, the α-LA diet emptied faster from the stomach. Dry matter recovery was higher in the stomach contents of rats fed the WPC diet than in those given the α-LA diet, but dry matter content in the small intestine was comparable. TCA soluble protein levels in the stomach and the small intestinal contents were also significantly (P &lt 0.001) higher in rats fed the WPC diet. The concentration of peptides having molecular weights (MW) ranging from 12 500–30 000 daltons (Da) was higher in the stomach contents of rats fed the WPC diet. Conversely, the level of peptides ranging from 5000–12 500 Da was higher in the stomach contents of rats fed the α-LA diet. For both diets, the small intestinal contents were characterized by high levels of amino acids and small peptides. These results suggest that the hydrolysis and absorption of α-LA is faster than that of WPC.Key words: In vivo protein digestion, peptides absorption, whey protein concentrate, α-lactalbumin, stomach emptying.

Pancreatic secretory response to feeding in the calf: CCK-A receptors, but not CCK-B/gastrin receptors are involved

In bovine species, as in human, the pancreas predominantly expresses cholecystokinin-B (CCK-B)/gastrin receptors. However, the role of this receptor in the regulation of meal-stimulated pancreatic enzyme release has not been determined. In milk-fed calves, we previously described prandial patterns of exocrine pancreatic secretion and a long prefeeding phase was observed. The present study was aimed at determining both the role of external stimuli in the outset of the prefeeding phase and the implication of pancreatic CCK-A and CCK-B/gastrin receptors in the mediation of pancreatic response to feeding. The first objective was studied by suppressing external stimuli associated with food intake (unexpected meal) and the second by infusing highly specific and potent antagonists of CCK-A (SR 27897) and CCK-B/gastrin (PD 135158) receptors during the prandial period. When calves were given an unexpected meal, the long prefeeding increase in pancreatic secretion was absent. SR 27897 (but not PD 135158) inhibited the preprandial phase and greatly reduced postprandial pancreatic juice and enzyme outflows. The expectancy of a meal seemed to elicit an increased pancreatic response right before a meal and CCK-A receptors may mediate this information via neural pathways. The implication of CCK and CCK-A receptors in mediating the postfeeding pancreatic response was also demonstrated. The participation of CCK-B/gastrin receptors in this regulation was not demonstrated.Key words: CCK-A and CCK-B/gastrin receptors, cholecystokinin, exocrine pancreatic secretion, feeding, milk-fed calf.

Effects of hydrolyzed spray dried red blood cells in milk replacer on calf intake, body weight gain, and efficiency

An alternative protein ingredient based on spray-dried, hydrolyzed red blood cells was evaluated in calf milk replacers. Two experiments were conducted to determine the value of the ingredient on intake, growth, and feed efficiency in dairy calves. In experiment 1, Holstein bull calves (n = 120) were fed calf milk replacer containing 0, 11, 22, or 43% of crude protein as spray dried hydrolyzed red blood cells. Calves were fed 454 g/d of experimental milk replacer reconstituted to 12% dry matter plus a conventional calf starter for 28 d. Body weight gain, intake of milk replacer and calf starter, feed efficiency, fecal scores, and days scouring were unaffected by source of protein. In experiment 2, Holstein calves (n = 69) at the University of Minnesota, Crookston and Waseca were fed milk replacer containing 0, 22, or 43% of crude protein as spray dried hydrolyzed red blood cells. Calves were fed 454 g/d of experimental milk replacer reconstituted to 12% dry matter plus a conventional calf starter containing 0 or 25% alfalfa meal for 35 d. No calves died during the study. Body weight gain, feed efficiency, intake of calf starter and milk replacer, fecal scores, and days scouring were unaffected by increasing hydrolyzed red blood cells in milk replacer. Similar performance of all calves indicated that spray dried hydrolyzed red blood cells can replace up to 43% of crude protein from whey protein concentrate without detrimental effects on animal performance.