Effect of diet on disaccharidase activity in the chick

Prebiotics can restrict Salmonella populations in poultry: a review

Antibiotics were over the years, the common supplement used for poultry production. There is a global trend to lessen antibiotics' use due to the contamination of consumed meat with antibiotic residues. Also, there is a concern that human treatments might be jeopardized due to the emergence of antibiotic-resistant bacteria. Prebiotics are attractive supplements, particularly in poultry production, because of the diversity of their effects, including pH amendments, production of short-chain fatty acids (SCFA) and the inhibition of pathogens' growth. The commonly used prebiotics are carbohydrate sources that cannot be easily broken down by chickens. However, they can efficiently be utilized by the intestinal tract's microflora. Oligosaccharides, polysaccharides and lactose are non-digestible carbohydrate sources that are typically used in poultry diets as prebiotics. This review covers current applications and prospects for using prebiotics to improve poultry performance and reduce pathogens, particularly Salmonella, in gastrointestinal tract.

Low inclusion levels of Tenebrio molitor larvae meal in laying Japanese quail (Coturnix japonica, Gould, 1837) diet improve the intestinal morphometry, enzymatic activity and caecal short chain fatty acids profile

One hundred twenty, 12 weeks old laying Japanese quails (JQ) were equally divided into 4 groups (6 replicates of 5 birds/group). The control group (CON) fed a corn-soybean diet; TML1.4, TML2.8, and TML5.6 groups fed a diet where a Tenebrio molitor larvae meal (TML) was included at 1.4, 2.8, and 5.6%, respectively. The trial lasted 54 days. The villi height (VH) and the crypt depth (CD) linearly decreased from the control to the TML5.6 group (P < 0.01) in the duodenum, while an opposite trend was observed for the Ab+ mucous cells count (P < 0.01). The highest VH/CD ratio was found in the TML1.4 group (P < 0.01). In the jejunum a lower VH was observed in the TML1.4 compared to the CON group; the Ab+ mucous cells increased (P < 0.01) according to the increase of the TM inclusion in the diet, while the highest VH/CD ratio (P < 0.01) was recorded in the TML2.8 group. In the duodenum only the L-ANP has been affected by TML (P < 0.001), with a quadratic and linear effect. The L-ANP is affected by the dietary treatment in the jejunum (P < 0.05), where showed a quadratic effect with the highest value in TML2.8. The % of butyric acid is maximized (P < 0.05) with the TML1.4 diet and that of the isobutyrate and valeric acids increased (P < 0.01) from TML1.4 to TML5.6. The use of TML at 1.4% in laying quail diets can be considered as a way to improve the intestinal health of the birds.

Macronutrient signals for adaptive modulation of intestinal digestive enzymes in two omnivorous Galliformes

According to the adaptive modulation hypothesis, digestive enzyme activities are matched to their respective dietary substrate level so that ingested nutrients are not wasted in excreta due to insufficient digestive capacity, and so membrane space or expenditures building/maintaining the intestinal hydrolytic machinery are not wasted when substrate levels are low. We tested predictions in juvenile northern bobwhites (Colinus virginianus) and juvenile and adult domestic chickens (Gallus gallus domesticus) by feeding them on diets varying in starch, protein, and lipid composition for 7-9 d (bobwhites) or 15 d (chickens). Birds were euthanized, intestinal tissue harvested, and enzyme activities measured in tissue homogenates from proximal, medial and distal small intestine. We found that (1) α-glucosidase (AG; maltase and sucrase) activities were induced by dietary starch in both juvenile and adult chickens but not in northern bobwhites; (2) aminopeptidase-N (APN) activities were induced by dietary protein in both bobwhites and juvenile but not adult chickens; (3) AG activities were suppressed by an increase in dietary lipid in both bobwhites and juvenile but not adult chickens; and (4) APN activities were not suppressed by high dietary lipid in any birds. We review findings from 35 analogous trials in 16 avian species. 100% of avian omnivores modulate at least one enzyme in response to change in dietary substrate level. AG induction by dietary carbohydrate occurs in more members of Galloanserae than in Neoaves, and all omnivorous members of Neoaves tested so far increase APN activity on high dietary protein, whereas fewer of the Galloanserae do.

Influence of acidified drinking water on growth performance and gastrointestinal function of broilers

The ban on the use of antibiotic feed additives as growth promoters compelled the researchers for exploring the future utility of other alternatives. This experiment was designed to evaluate the effect of acidified drinking water on growth performance, gastrointestinal pH, digestive enzymes, intestinal histomorphology, and cecum microbial counting of the broiler chicken. A total of 540 one-day-old male broilers (Arbor Acre) were randomly assigned to 5 treatments, with 6 replicates of 18 chicks per replicate. Broilers received diets and water as follows: NC (negative control, basal diet, normal water), PC (positive control, basal diet + 8 ppm colistin sulfate + 8 ppm enduracidin, normal water), A1 (basal diet, continuous supply of acidified water during whole experiment period), A2 (basal diet, intermittent acidification of water during 0 to 14 d, 22 to 28 d, and 36 to 42 d), and A3 [basal diet, intermittent acidification of water (24 h/d from 0 to 14 d and from 10:00 am to 4:00 pm on d 15 to 42)]. During the entire period, the acidified groups (A1, A2, and A3) and PC group showed improve on weight gain, average daily gain and feed conversion ratio compared to NC group (P < 0.05). The pH in crop, proventriculus and ileum at 43 d declined by 0.04, 1.03, 1.23; 0.55, 0.69, 0.70; and 0.63, 0.74, 1.21 in A1, A2, and A3 group, respectively. There was a significant decline of lipase activity in the PC and acidified groups compared to NC group. The A2 group had higher villus height in jejunum than NC group. The PC and acidified groups reduced (P < 0.05) the total aerobic bacteria count of cecum when contrasted to NC group. Therefore, we conclude that acidified drinking water can improve growth performance, compensate for gastric acidity, and control pathogenic bacteria in broilers and may be considered as a potential alternative to improve production parameters. Discontinuous supply of acidified water had the same or even better influence on broilers compared to continuous supply.

Modulation of digestive enzyme activities in the avian digestive tract in relation to diet composition and quality

In nature, birds are faced with variable food sources that may differ in composition (protein vs. carbohydrates) and quality (highly digestible material vs. indigestible fiber). Studies in passerine birds and some commercial poultry demonstrate that the gastrointestinal tract can respond to varying diet composition and quality by changing morphology and/or activities of digestive enzymes. However, studies in additional avian species are warranted to understand generalities of these trends. We first fed juvenile mallards (Anas platyrhynchos), chickens (Gallus gallus), and quails (Coturnix coturnix) on either high-carbohydrate or high-protein diets. For the most part, birds fed the high-carbohydrate diet had higher small intestinal and cecal disaccharidase activities (maltase and sucrase). However, only mallards exhibited higher small intestinal aminopeptidase-N (APN) activities when fed the high-protein diet. These results differ from passerine birds, which largely modulate small intestinal proteases, but not disaccharidases. In another trial, we fed Canada geese (Branta canadensis) diets that varied in both their protein and fiber concentrations for approximately 3.5 months. Birds fed the high-fiber diets had significantly longer small intestines and caeca compared to those fed low-fiber diets. Additionally, geese fed the high-fiber diets exhibited lower mass-specific activities of small intestinal sucrase, and higher activities of APN when summed across the small intestine and ceca. Similar to the avian species above, geese fed the high-protein diets did not exhibit flexibility in their small intestinal APN activities. Overall, these experiments demonstrate that responsiveness of the avian digestive tract to diet composition may have phylogenetic or ecological constraints. Studies on other avian taxa are needed to understand these patterns.

Effect of dietary threonine on laying performance and intestinal immunity of laying hens fed low-crude-protein diets during the peak production period

Threonine (Thr) may be a limiting amino acid for laying hens fed diets with lowered protein level. An experiment was conducted to examine laying performance, and the intestinal immune function of laying hens provided diets varying in digestible Thr levels. Lohmann Brown laying hens (n = 480), 28 weeks of age, were allocated to six dietary treatments, each of which included five replicates of 16 hens. Dietary crude protein (CP) 16.18% diet was offered as the positive control diet. L-Thr was added to the negative diet (14.16% CP) by 0, 1.0, 2.0, 3.0 and 4.0 g/kg, corresponding 0.44%, 0.43%, 0.49%, 0.57%, 0.66% and 0.74% digestible Thr. At 40 weeks, a reduction in CP level decreased laying performance (p < 0.05). In the low CP, increasing dietary Thr increased (p < 0.05) egg production and egg mass and rose to a plateau between 0.57% and 0.66%. The hens fed 0.66% Thr showed the lowest value (p < 0.05) of feed conversion ratio (FCR). Serum level of uric acid showed the lowest values (p < 0.05) at 0.57-0.66%. In addition, serum-free Thr maximized (p < 0.05) between 0.66% and 0.74%. Digestive trypsin activity decreased (p < 0.05) when hens fed the low-CP diet compared with hens fed CP (16.18%) and hens fed 0.57-0.66%. Expressions of ileal MUC2 mRNA maximized (p < 0.05) at 0.66% Thr. Occludin mRNA increased with increasing Thr level (p < 0.05). sIgA mRNA reached to the maximum level (p < 0.05) at 0.66% and 0.74% Thr. INF-γ mRNA reached to the lowest level (p < 0.05) at 0.65%. Expressions of ileal IL-2, IL-6, IL-1β mRNA decreased with increasing Thr level (p < 0.05). In conclusion, Thr supplementation resulting in optimal laying performance and stimulated the mucosal immune system, suggesting that it is a limiting amino acid in the low-crude-protein diet of laying hens during the peak production period.

Effects of dietary metabolizable energy and crude protein content on the activities of digestive enzymes in jejunal fluid of Peking ducks

The response of digestive enzymes activities in the jejunal fluid of Peking ducks to dietary ME and CP content was investigated. In experiment 1, jejunal digesta from 24 cannulated male white Peking ducks of 18 wk of age were collected for 1 h out of every 4 h beginning at 0930 h on d 16, 18, and 20 of the experiment. The activities of amylase, trypsin, and chymotrypsin in jejunal fluid were determined. In experiment 2, 72 male cannulated ducks were randomly sorted into 4 groups. Four treatments consisted of combinations of 3,050 and 2,800 kcal/kg of ME, and 17.50 and 14.40% CP content were available ad libitum. Jejunal digesta samples were collected for 1 h every 4 h from 0930 to 1830 h on d 31, 33, and 35 of the experiment according to the results of experiment 1. The activities of amylase, trypsin, chymotrypsin, lipase, sucrase, and maltase in jejunal fluid were determined. In experiment 1, significant differences were found in the average activities of amylase and chymotrypsin among days. The collection time significantly affected the 3 enzyme activities, and average enzyme activities during the day were higher and more stable than during the night. In experiment 2, the effect of dietary ME content on the 6 digestive enzymes activities was not significant. But the dietary protein content significantly changed amylase, trypsin, and chymotrypsin activities.

Effects of Feed Restriction and Realimentation on Digestive and Immune Function in the Leghorn Chick

How regulatory changes of digestive and immune functions of the gut influence each other has not been sufficiently studied. We tested for simultaneous changes in the digestive physiology and mucosal immune function of the guts of White Leghorn cockerel chicks undergoing food restriction and realimentation. Chicks were assigned to 1 of 3 groups: control = fed ad libitum 7 to 17 d of age; restricted = feed restricted d 12 to 17 (at 2 restriction levels: 54 and 34% ad libitum); refed = feed restricted d 7 to 13 and then fed ad libitum d 14 to 17. Refed chicks exhibited 1 d of hyperphagy and an increase in apparent digestive efficiency following restriction (ANOVA, P < 0.001). Total small intestine mass and duodenal maltase activity differed among the groups in the order refed > control > restricted, as expected (ANOVA, P < 0.05 for both measures). In contrast, there were no significant treatment effects on our measures of gut immune structure and function, including bursa mass, spleen mass, and total IgA content of intestinal flush samples measured with standard ELISA techniques. The results of this study indicated that, during feed restriction and realimentation, some features of gut immune function are maintained unchanged in the face of regulatory changes that influence digestive functions.

Development of disaccharidase activity in the small intestine of broiler chickens

1. The changes in disaccharidase activity in the small intestine of broiler chickens were investigated in isolated enterocytes on d 18 of embryonic development and d 1, 7, 21, 35 and 56 after hatching. 2. The specific activities of maltase, lactase and trehalase were greatest on d 18 of embryonic development. After hatching, maltase specific activity gradually decreased until d 18. 3. After d 7 postnatally only traces of lactase and trehalase activity were found in the enterocytes. 4. Significant sucrase activity was found on d 18 of embryonic development and the activity of this enzyme increased 2-fold after hatch and remained generally constant up to d 35, after which the enzyme specific activity declined.

An experimental test of dietary enzyme modulation in pine warblers Dendroica pinus

Modulation of gut function is important in an ecological and evolutionary context because it likely determines what food items an animal can and cannot eat. We examined how diet affects activity of digestive enzymes in an omnivorous bird, the pine warbler (Dendroica pinus). Pine warblers were fed insect-based, fruit-based, and seed-based diets for approximately 54 d. We then measured activity of amylase, maltase, sucrase, aminopeptidase-N, trypsin, chymotrypsin, carboxypeptidase A, carboxypeptidase B, pancreatic lipase, and carboxyl ester lipase. We predicted that carbohydrase activities would be highest in birds fed the diet highest in carbohydrates (fruit based), protease activities would be highest in those fed the diet highest in protein (insect based), and lipase activities would be highest in those fed the diets highest in lipid (insect based and seed based). Also, we predicted that pine warblers would exhibit greater dietary modulation of enzyme activity than reported for a less omnivorous congener, the yellow-rumped warbler (Dendroica coronata). All predictions were upheld, supporting the hypothesis that pine warblers modulate the activity of digestive enzymes in proportion to demand from substrates in the diet.

The effects of delayed access to feed and water on the physical and functional development of the digestive system of young turkeys

Three experiments were conducted with turkeys to determine the influence of delayed access to feed and water on the development of the digestive system. In all experiments, poults were randomly assigned to three placement times, 6, 30, and 54 h posthatch. Experiments 1, 2, and 3 were terminated when poults were 10, 28, and 14 d old, respectively. In Experiment 1, six poults per treatment were sampled on Days 1, 2, 3, 4, 5, 6, 8, and 10. In Experiment 2, 12 poults per treatment were sampled on Days 1, 2, 3, 4, 5, 10, 15, and 28. The objective of Experiment 3 was to determine the effect of delayed placement on dietary MEn. Delaying access to feed and water for 54 h adversely affected BW through 10, 28, and 14 d of age in Experiments 1, 2, and 3, respectively (P < or = 0.01). Delayed access to feed and water for 54 h decreased the absolute weights of the small intestine and pancreas and reduced lengths of the small intestine through 5 d posthatch (P < or = 0.05). The relative weights of the small intestine and proventriculus were reduced by delayed access to nourishment through 4 d posthatch. Poults placed on feed at 54 h posthatch had decreased pancreatic amylase activity (P < or = 0.05) at 3 and 4 d, and trypsin activities were depressed at 3 d posthatch (P < or = 0.05). In Experiment 3, dietary MEn value determined at 4 d of age with poults placed 54 h posthatch was less (P < or = 0.07) than the MEn value obtained with poults placed at 6 h posthatch. A 54-h delay in access to feed and water generally delayed development of the digestive system, impaired nutrient utilization, and reduced BW.

Intestinal absorption of D-galactose and L-leucine and intestinal disaccharidase activities in growing chickens fed different raw legume diets

A significant (P less than .01) impairment in the rate of growth, along with a significant (P less than .01) inhibition in the rate of in vivo intestinal absorption of D-galactose and L-leucine, and in the in vitro intestinal absorption of D-galactose, was found in growing chickens fed ad libitum over a 60-day period, diets containing the raw legumes Vicia faba, Glycine soja, Vicia ervilia, and Phaseolus vulgaris as the main source of protein. Furthermore, a significant (P less than .01) reduction in the intestinal disaccharidase activity was found in the legume-fed chickens. The possible nature of these effects was discussed.

Ontogenesis of intestine morphology and intestinal disaccharidases in chickens (Gallus gallus) fed contrasting purified diets

Two groups of growing posthatching Cornish x Rock cross chickens were fed with either a carbohydrate-containing (52.5%) or a carbohydrate-free diet. At 36 days after hatching some of the chicks in each group were shifted to the opposite diet. Chickens fed on a carbohydrate-containing diet grew faster and achieved higher asymptotic masses than chickens fed on a carbohydrate-free diet. Chickens fed on a carbohydrate-free diet had longer intestines and larger intestinal areas than chickens of the same mass fed on a carbohydrate-containing diet. In both groups sucrase and maltase activity (standardized by either intestinal area or mass) increased from day 1 to approximately day 17. After day 17, chickens fed on a carbohydrate-containing diet exhibited 1.8 and 1.9 times higher sucrase and maltase activities per unit intestinal area, respectively, than chickens fed on a carbohydrate-free diet. Analysis of covariance was used to estimate the contribution of sucrase and the sucrase-independent maltases to maltase activity, and to estimate the effect of diet on the sucrase-independent maltases. Sucrase contributed 80% and 75% of the maltase activity in carbohydrate and carbohydrate-free fed chickens, respectively. Chickens shifted from a carbohydrate-free to a carbohydrate diet converged in gross intestinal morphology and intestinal sucrase and maltase levels with carbohydrate-fed chickens within 8 days. Chickens shifted from carbohydrate to carbohydrate-free diets, in contrast, did not show appreciable changes in intestinal length and after 8 days had not reduced levels of sucrase and maltase to those of chickens fed on the carbohydrate-free diet. A comparison of integrated maltase intestinal activity with published data on glucose uptake showed that the ratio of maltose hydrolysis to glucose uptake seemed to be about 7 and to remain relatively invariant during ontogeny. Because so little is known about the interaction between hydrolysis and uptake in vivo, it is difficult to determine if this relatively high ratio represents excess hydrolytic capacity or if it is needed to provide high lumenal glucose concentrations that maximize uptake.