Relative Intestinal Length Research Articles

Meal timing affects protein-sparing effect by carbohydrates in sea bream: Effects on digestive and absorptive processes

Abstract A commercial diet (C) (48% protein and 20% lipids) and a high-digestible carbohydrate diet (CH) (37% protein, 12.5% lipids and 40% high-digestible carbohydrates) were used to feed sea bream juveniles for an 8-week period. In the commercial diet, more than 60% of ingredients were of plant origin from various sources, whereas the only component of plant origin in the CH diet was wheat. To determine the best time to administer carbohydrates and the possible protein-sparing effect, three different dietary regimes were established: C, CH-M and CH-A, and the corresponding diet was fed to sea bream in the morning (1.6% of bw) and in the afternoon (1% of bw), calculating quantities according to the amount of feed that fish ate during the acclimatization period. After the growth trial, specific growth rate (SGR), relative intestinal length, intestinal pH content, gastric and pancreatic digestive enzyme activities and nutrient absorption capacities were studied 5 h post-feeding after each meal (morning and afternoon). The acid protease activity measured was anticipatory and was higher when the next meal would have more protein. No differences in relative intestinal length or feed buffering capacity were found. The smaller ration given to sea bream in the afternoon led to a lower pancreatic release of alkaline protease and α-amylase and an up-regulation of D-Glc and L-Ala absorption capacity. A higher transit rate was measured when sea bream were fed the CH diet. When high-digestible carbohydrates were administered in the morning and the commercial diet in the afternoon, we observed a better assimilation of both diets due to compensatory mechanisms such as an increase in L-Lys, D-Glc and L-Ala absorption capacity after the morning feed, and a higher pancreatic release of alkaline protease and amylase after the afternoon feed. In contrast, when high-digestible carbohydrates were given in the afternoon, only a significant up-regulation of the capacity to absorb L-Lys was detected. Thus, the inclusion of high-digestible carbohydrates in the diet improved digestion and absorption processes when administered in the morning, leading to a protein-sparing effect that yielded growth comparable to that of fish fed an exclusively commercial diet.

Histomorphological Comparison of Proventriculus and Small Intestine of Heavy and Light Line Pre- and at Hatching

Gross, histomorphometric and histochemical comprasion of proventriculus and small intestinal segments were determined in heavy and light line at last day’s incubation. Five embryos from each line were used at 16 day, 19 day and 21 day incubation. The weight of the proventriculus, yolk sac and weight in addition to the length of each separated straightened intestinal segments were recorded. Histological samples were stained with Harris Hematoxylin and Eosin, Masson’s Trichrome stain for histological structures, combined Alcian blue-PAS and Aldehyde Fuschin-Alcian blue stain for mucin classification. The thickness of wall layers of these organs were determined, measurement of villus height, villus surface area and height of epithelial mucosa of each intestinal segments (duodenum, jejunum and ileum) were recorded. The relative weight of yolk sac, proventriculus, jejunum and ileum were significantly higher in heavy line. The relative length of intestine was not constant between breeds. However, the heavy line had longer jejunum and ileum at 16 day and 21 days incubation. Histologically, the well- developed proventricular glands and epithelial folds appeared since 16 day incubation in both breeds. The thicknesses of these glands was greater in heavy line. The duodenal of heavy line had dominantly longer villi with higher villus surface area, for jejunam was restricted at 21 days only. Similar pattern was found for epithelial height and number of goblet cells in intestinal mucosa. The histochemical observations showed presence of neutral and acidic mucin in intestinal epithelium with most mucous cells were had sulphated mucin. Intestinal development patterns were similar for both lines but growth was more rapid in heavyline than the light line.

Intestinal development and function of broiler chickens on diets supplemented with clinoptilolite.

The purpose of this study was to evaluate the effect of natural clinoptilolite (NCLI) and modified clinoptilolite (MCLI) on broiler performance, gut morphology, intestinal length and weight, and gut digestive enzyme activity. A total of 240 d-old male chicks were randomly assigned to 3 treatments, each of which comprised 8 pens of 10 chicks per pen. Birds in the control group were fed the basal diet, while those in the experimental groups were fed diets supplemented with NCLI at 2% (NCLI group), or MCLI at 2% (MCLI group), respectively, for 42 d. Compared with the control, supplementation with NCLI or MCLI had no significant (p>0.05) effects on productive parameters from d 1 to 42. Supplementation with NCLI or MCLI had no influence on the relative length and weight of small intestine at d 1 to 21. But supplementation with NCLI or MCLI significantly reduced the relative weight of duodenum. Supplementation with MCLI and NCLI was associated with greater (p<0.05) villus height in the jejunal and ileal mucosa compared with those areas in the controls from d 1 to 42. However, supplementation with NCLI and MCLI had no significant (p>0.05) influence on the crypt depth in the jejunal and ileal mucosa compared with those in the controls. The addition of either NCLI or MCLI to the diet improved the activities of total protease, and amylase in the small intestinal contents. In conclusion, supplementation with NCLI or MCLI in diets improved intestinal morphology, increased the intestinal length and weigh and gut digestive enzyme activity.

Spray-dried porcine plasma and yeast derived protein meal influence the adaption to weaning of primiparous and multiparous sow progeny in different ways

Pigs from 154 litters (n = 1132, 19 ± 3 days of age, 4.9 ± 1.1 kg of bodyweight) were used in a 3 × 2 factorial design to evaluate two raw materials with nutraceutical properties being used in feeds, spray-dried porcine plasma (SDPP) and a yeast protein meal, and their effects on growth performance, immune parameters and gastrointestinal adaption of piglets to weaning. Factors included dietary treatments being (1) 5% SDPP (PLA), (2) 3.5% yeast protein meal (NUP) and (3) medicated control (TMC) and parity (primiparous versus multiparous). The treatment groups were imposed from Day 19 through to weaning at Day 27. Selected pigs (n = 720, 28 ± 3 days of age, 7.4 ± 1.0 kg of bodyweight) were weaned and remained on their respective diets from Day 28 to Day 34. From Day 35 to Day 48 all group-housed pigs were offered a commercial weaner 1 diet, and from Day 49 to Day 68 pigs were offered a commercial weaner 2 diet. Growth performance, survival, and serum immunoglobulin G were monitored throughout the nursery phase (Day 28 to Day 68). Adaptation of the gastrointestinal tract in the acute post-weaning phase (Day 28 to Day 34) was assessed in 36 individually housed male weaners, with the effects of feed on structural, digestive, microbial and immune parameters along the gastrointestinal tract determined at Day 34. Pre-weaning feed disappearance was greater (P &lt; 0.01) in multiparous litters independent of diet. In the commercial nursery, total removals (mortality and morbidity) were highest (P &lt; 0.01) in primiparous sow progeny, with pigs offered NUP having greater (P ≤ 0.05) total removals. Pigs offered PLA had superior average daily gain, average daily feed intake and feed conversion ratio from Day 28 to Day 34 (P &lt; 0.05). Pigs offered NUP tended to (P = 0.07) have superior average daily gain from Day 35 to Day 49. Pigs offered NUP had higher (P &lt; 0.05) serum immunoglobulin G concentrations at Day 68 compared with pigs offered TMC, with the effect most pronounced in primiparous sow progeny. Individually housed weaners offered PLA consumed more (P &lt; 0.05) feed on Day 30 to Day 31, had shorter relative intestine length (P &lt; 0.05), greater villous height in the medial jejunum (P &lt; 0.10) and lower immuno-pathology scores along the intestine. Pigs offered PLA also tended (P &lt; 0.10) to have increased pancreatic-specific lipase and amylase activity compared with pigs offered NUP. Pigs offered NUP had a higher ratio of E. coli : coliforms in the colon (P &lt; 0.01) and more counts of β-haemolytic bacteria in the medial jejunum (P &lt; 0.05) and colon (P &lt; 0.10). Diets containing either SDPP or NUP offered pigs benefits beyond nutrition relative to the medicated control diet. The benefits of SDPP were highly effective but transient, while the yeast derived protein had a successive or accumulative effect which was more pronounced in primiparous sow progeny.

Enzyme-producing bacteria isolated from fish gut: a review

Digestion of food depends on three main factors: (i) the ingested food and the extent to which the food is susceptible to the effects of digestive enzymes, (ii) the activity of the digestive enzymes and (iii) the length of time the food is exposed to the action of the digestive enzymes. Each of these factors is affected by a multitude of secondary factors. The present review highlights the experimental results on the secondary factor, enzymatic activity and possible contribution of the fish gut microbiota in nutrition. It has been suggested that fish gut microbiota might have positive effects to the digestive processes of fish, and these studies have isolated and identified the enzyme-producing microbiota. In addition to Bacillus genera, Enterobacteriaceae and Acinetobacter, Aeromonas, Flavobacterium, Photobacterium, Pseudomonas, Vibrio, Microbacterium, Micrococcus, Staphylococcus, unidentified anaerobes and yeast are also suggested to be possible contributors. However, in contrast to endothermic animals, it is difficult to conclude the exact contribution of the gastrointestinal microbiota because of the complexity and variable ecology of the digestive tract of different fish species, the presence of stomach and pyloric caeca and the relative intestinal length. The present review will critically evaluate the results to establish whether or not intestinal microbiota do contribute to fish nutrition.

The effects of starvation on digestive tract function and structure in juvenile southern catfish (Silurus meridionalis Chen)

The size and functional capacity of the gastrointestinal (GI) tract and associated organs vary in response to environmental cues. The GI tract and associated organs are also very metabolically active in animals. Hence, animals may reduce the size and function of their GI tract to conserve energy when deprived of food. The main aims of this study were to investigate how Silurus meridionalis regulates the function and structure of its GI tract and associated organs during starvation. Starvation induced a decrease in both maintenance metabolism (MO2rest, decreased by approximately 50%) and respiratory frequency (indicated by double side gill activity and notated as fR, decreased by 29%). Lipase, trypsin and aminopeptidase-A showed a similar reduction in mass-specific activities during starvation, but pepsin and α-amylase did not. The starvation of experimental fish resulted in a significant reduction in body weight, the wet mass of the liver and the digestive-somatic system, the hepato-somatic index and the condition factor whereas the wet masses of the GI tract, pancreas, gall bladder and the relative intestinal length did not vary significantly during starvation. The reduction in liver wet mass was the main reason for the decrease in the wet mass of digestive-somatic system in this species. Only the mucosal area of the PI was affected significantly by starvation, decreasing by 34% at the end of the experiment. S. meridionalis displayed a decreasing intestinal mucosal area towards the distal intestine, and this gradient was not affected by starvation. The morphology and structure of both the GI tract and the liver were greatly down-regulated, as indicated by decreases in liver cell size, the mucosal thickness of the stomach and intestine, the density of goblet cells and microvilli surface area (MVSA), implying that food deprivation greatly impaired the digestive and absorptive functions of the GI tract in S. meridionalis. When deprived of food, S. meridionalis can endure harsh periods of starvation and adaptively down-regulate the function and structure of the digestive tract with physiological and biochemical strategies.

Effect of dietary nucleotide supplementation on performance and development of the gastrointestinal tract of broilers

1. Two experiments were conducted to determine the effects of dietary nucleotide supplementation on broiler performance, and physical and morphological development of the gastrointestinal tract. 2. Experiment 1: A total of 180 one-d-old male chicks were placed in battery brooders in 3 × 6 replicate pens containing 10 chicks each. Chicks were randomly assigned to one of the three dietary treatments; a maize-soyabean meal based diet supplemented with 0, 0·25, and 0·50% Torula yeast RNA (as a source of nucleotides) from 0 to 16 d of age. 3. Experiment 2: A total of 1344 one-d-old male chicks were placed in floor pens and reared on recycled wood shavings (two flocks) under a high stocking density (0·068 m2/bird). Chicks were randomly assigned to one of the 4 dietary treatments (0, 0·25% Torula yeast RNA, 2% and 6% Nupro®) for the starter period (0 to 14 d of age) with 6 replicate pens containing 56 chicks each. All the birds were fed on the same common grower diet with no supplementation of nucleotides from 15 to 32 d of age. 4. Experiment 1: Supplementing the diets with up to 0·50% Torula yeast RNA did not affect broiler performance, or relative intestinal tract weight and length of broilers at any periods measured. 5. Experiment 2: From 0 to 14 d of age, broilers fed on the diets supplemented with 0·25% Torula yeast RNA and 2 and 6% Nupro® were significantly heavier and had improved feed conversion (feed:gain) ratios as compared with the birds fed on the control diet. Supplementing the starter diet only with 2% Nupro® supplementation significantly improved body weight (BW) gain as compared with the control diet over the entire experiment (0 to 32 d of age). Broilers fed on the diets supplemented with 2 and 6% Nupro® from 0 to 14 d of age had better feed conversion (feed:gain) ratios over the entire experiment (0 to 32 d of age) as compared with the birds fed on the control diet, even though the birds were only fed on the diets supplemented with Nupro® from 0 to 14 d of age. The broilers fed on the diets supplemented with 0·25% Torula yeast RNA and 2% Nupro® had higher villus height and an improved villus height-to-crypt depth ratio as compared with birds fed on the control or 6% Nupro® diet at 14 d of age. 6. It is generally assumed that nucleotides are not an essential nutrient; thus there is no need to supplement the diets of broilers reared under normal conditions. However, dietary nucleotide supplementation may be important to maintain maximum growth performance when birds are exposed to stress conditions, such as high stocking density combined with dirty litter.

Morphological and histochemical study of intestine in wild and reared European eel (Anguilla anguilla L.)

Diet-related differences between the ratio of intestine length to body size and the enzymatic activity in the intestinal tract of wild and reared European eel (Anguilla anguilla L.) were studied. Compared with reared eel, wild eel showed significantly shorter relative intestine length. For the purpose of histochemical examination, different parts (anterior, middle and posterior) of intestine proper were used. Activities of non-specific esterase, alkaline and acid phosphatase, and aminopeptidase were examined in each segment. All enzymes were present in the intestines of both wild and reared European eel. Fish from both groups showed similar enzyme distribution within the enterocytes, but distribution and intensity of enzyme activity along the intestine vary depending on the group. Generally, reared European eel showed highest enzymatic activity and wider distribution of enzymes throughout all parts of the intestine. These results suggest that different diets could be one of the reasons for observed changes.

Detoxified Jatropha curcas kernel meal as a dietary protein source: growth performance, nutrient utilization and digestive enzymes in common carp (Cyprinus carpio L.) fingerlings

Jatropha curcas kernel meal is rich in protein; however, it is toxic. Two durations of detoxification process were investigated: 30 and 60 min; designated as Ja and Jb, respectively. Common carp fingerlings (252 fish; 3.2 ± 0.07 g) were fed diets: control containing fishmeal (FM); S50, Ja50 and Jb50: 50% of FM protein replaced by soybean meal (SBM), detoxified Jatropha kernel meal (DJaKM and DJbKM); S75, Ja75 and Jb75: 75% of FM protein replaced by SBM, DJaKM and DJbKM. Highest body mass gain, specific growth rate, metabolic growth rate (MGR) and energy production value were observed for the Jb50 group which were statistically similar to that for control group and significantly (P 0.05) for control and Jb50 groups, and these values were highest among the groups. Highest crude protein efficiency was observed in Jb50 group, whereas lowest in Jb75 group. Relative intestinal length and hepatosomatic index were higher in plant protein–fed groups. Intestinal amylase, protease and lipase activities for control group were statistically higher (P < 0.05) than for plant protein–fed groups. Conclusively, performance of Jb50 group was similar to control group and better than other groups and, thus, is recommended as the most optimal diet for common carp fingerlings.

Digestive enzymes along digestive tract of a carnivorous fish Glyptosternum maculatum (Sisoridae, Siluriformes)

This study attempted to determine the presence, distribution and levels of digestive proteases, pepsin, amylase and lipase in the homogenates of digestive tract of a freshwater, cold-adapted, carnivorous teleost of Tibet, Glyptosternum maculatum (n= 10, mean weight: 129.6±28.9 g, mean length: 195.1±16.6 mm, approximately 6 years old), at different temperatures and pH levels. The descending order of protease activity was as follows: stomach (pepsin, 16.16±0.96 U/mg protein), anterior intestine (3.18±0.25 U/mg protein), posterior intestine (1.76±0.21 U/mg protein) and middle intestine (1.52±0.23 U/mg protein). Amylase activity levels in descending order were as follows: anterior intestine (0.0062±0.0007 U/mg protein), stomach (0.0032±0.0009 U/mg protein), middle intestine (0.0023±0.0005 U/mg protein) and posterior intestine (0.0023±0.0004 U/mg protein). The highest lipase activity was found in the anterior intestine (0.83±0.25 U/mg protein), followed by posterior intestine (0.51±0.19 U/mg protein), middle intestine (0.48±0.09 U/mg protein) and stomach (0.39±0.10 U/mg protein). The optimal temperature and pH level for protease were 50°C and 9.0-10.0, respectively, along the intestine. The pepsin optima in the stomach were 30°C and 2.0 respectively. The optimal temperature for amylase was found to be 30°C along the digestive tract and the optimal pH was 7.0 in the intestine and 6.0 in the stomach. The optimal temperature and pH levels of lipase were 30°C, pH 6.0 for the stomach and 40-50°C, pH 8.0 for the intestine, respectively. Hepato-somatic index was 1.35±0.2% and relative intestine length was 0.90±0.19. The weight ratio of the stomach and intestine to body weight was 1.63±0.43% and 1.57±0.24% respectively.

Light and Scanning Electron Microscopy of the Intestine of the Young Red Jungle Fowl (Gallus gallus)

Thirty males of Red Jungle Fowl (RJF) were divided into 3 equal groups, euthanized at day 1, 10 and 20 days after hatching. The morphometric analyses were performed at three different magnification levels. Different segments (duodenum, jejunum and ileum) and cecum were weighted and length of each small intestinal segments and cecum were determined at a macroscopic level. The mucosa of the intestinal segments was compared and contrasted using both, light and scanning electron microscopy. The villi height, villi surface area, crypt depth and muscularis externa were measured. The body weight was doubled at 10th day and again doubled at 20th day. The weight and length of intestinal segments were significantly higher throughout the experiment except the constant rate of the duodenal and jejunal lengths after 10th days. Relative to body weight, the organs weight and length were declined after 10th days. The duodenal villi height and surface area were greater than the jejunum followed by the ileum. The muscularis externa and crypt depth increased significantly at 10th day. However, the latter showed retardation thereafter. Day one intestinal villi appeared finger-like shape with zigzag arrangement, tongue-like and leaf-like shaped in 10 and 20th days, respectively. The villi distribution and patterns in the middle region of cecum were characteristic. The epithelial cells of the duodenal villi showed more activities and development than those on the jejunum and the ileum throughout the age. The body growth in RJF progresses very slowly while the relative intestinal segment weight and length failed to follow the body weight after 10th days. The duodenal mucosa shows better developmental features than the jejunum and the ileum.

Nutritional, physiological and haematological responses in rainbow trout (Oncorhynchus mykiss) juveniles fed detoxified Jatropha curcas kernel meal

Jatropha curcas is a multipurpose and drought-resistant tree, widespread throughout tropics and subtropics. Its seeds are rich in oil and protein. It is being promoted as a biofuel plant. Jatropha kernel meal obtained after oil extraction is an excellent source of protein [580-660 g kg⁻¹ crude protein (CP)]. However, the presence of toxic and antinutritional constituents restricts its use in fish feed. Jatropha kernel meal was detoxified. Using Oncorhynchus mykiss juveniles, a 12-week experiment was conducted to evaluate the nutritional quality of detoxified Jatropha kernel meal (DJKM). Oncorhynchus mykiss juveniles (36, av. wt. 4.2 ± 0.4 g) were distributed into three groups with 12 replicates and fed isonitrogenous (CP 450 g kg⁻¹) diets: control [fish meal (FM)-based protein], J₅₀ and J₆₂.₅ (50% and 62.5% of fishmeal protein replaced by DJKM). Growth performance, apparent lipid conversion, hepatosomatic index, nutrients and energy digestibilities; efficiency of digestible nutrients and energy; and glucose and creatinine levels in blood were statistically similar (P > 0.05) for control and J₅₀ but were higher (P < 0.05) than for J₆₂.₅. Opposite trend was observed for phosphorus, sodium, albumin and total protein in blood. Feed conversion ratio, protein efficiency ratio, protein productive value, energy retention, gastro somatic index, muscle lipid peroxide; and red and white blood cells, haematocrit, haemoglobin, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration; alkaline phosphatase and alanine transaminases activity, globulin, total bilirubin, blood urea nitrogen, calcium and potassium in blood and lysozyme activity in serum did not differ significantly among the groups. Intestinal enzyme activities; and plasma and muscle cholesterol levels for control were higher (P < 0.05) than for DJKM groups, while opposite trend was observed for relative intestinal length (mm g⁻¹). Conclusively, performance of J₅₀ group was similar to control group and, thus, is recommended as the optimal diet for rainbow trout.

Trophic polymorphism and water clarity in northern Australian Scortum (Pisces: Terapontidae)

Davis AM, Pusey BJ. Trophic polymorphism and water clarity in northern Australian Scortum (Pisces: Terapontidae). Ecology of Freshwater Fish 2010: 19: 638–643. © 2010 John Wiley &amp; Sons A/SAbstract – The diets and relative intestinal length of two typically herbivorous terapontid fish from contrasting high and low clarity environments were compared. Fish of both species collected from high clarity habitats were almost exclusively herbivorous, whereas conspecifics from low clarity habitats were omnivores. Relative intestinal lengths in both species were significantly shorter in low clarity environments. Pronounced contrasts in water transparency have the apparent capacity to produce dietary niche shifts in these two species that in turn induce and maintain trophic polymorphisms in a riverine environment.

Effect of grape seed extract on growth performance, protein and polyphenol digestibilities, and antioxidant activity in chickens

Grape seed extract (GSE) provides a concentrated source of polyphenols that have antioxidant capacity. An experiment was conducted to investigate the effect of GSE at levels 0.6, 1.8 and 3.6 g kg-1 in broiler chicks (1 to 42 days) on growth performance, relative weights (pancreas, spleen and liver) and lengths (duodenum, jejunum, ileum and ceca) of digestive organs, relative weights of liver fat and abdominal fat, ileal protein digestibility, excreta extractable polyphenol digestibility, and antioxidant activity of diet and excreta. The inclusion of GSE did not affect the performance and the relative liver and pancreas weights. Relative intestinal length was reduced at 21 days of age by the inclusion of GSE. The inclusion of GSE caused an increase of relative spleen weight at 42 days of age. Ileal digestibility of crude protein was increased at 21 days of age in birds fed GSE diets. Excreta extractable polyphenol digestibility was increased at 21 and 42 days of age by the inclusion of GSE in the diets reaching values of 57 to 65 % and 60 to 69%, respectively. Antioxidant activity in GSE diets and excreta exhibited higher scavenging free radical capacity at 21 and 42 days than control diet. We concluded that GSE could be a new source of antioxidant in animal nutrition.

IUGR Does Not Predispose to Necrotizing Enterocolitis or Compromise Postnatal Intestinal Adaptation in Preterm Pigs

IUGR and preterm birth are leading causes of neonatal morbidity. We tested the hypothesis that IUGR predisposes to gut maladaption and necrotizing enterocolitis (NEC) using preterm pigs as models for preterm infants. First, full-term normal birth weight (NW) and IUGR ( approximately 65% of NW) pigs were compared. IUGR reduced intestinal weight per length, proportion mucosa, villous area, and sucrase activity at 2 d after birth (p < 0.05) but did not change relative organ weights. Next, groups of preterm pigs were fed formula or colostrum, starting at birth or after 2-3 d of total parenteral nutrition (TPN). Neonatal mortality (not related to NEC) was increased in IUGR versus NW preterm pigs (28 vs 10%, p < 0.01). NEC incidence was similar between IUGR and NW but higher after formula than colostrum feeding (46 vs 12%, p < 0.01) and higher after TPN than without TPN (61 vs 34% for formula pigs, p < 0.01). After feeding, relative intestinal mass and length were higher in IUGR versus NW pigs (+25-80%, p < 0.05) while brush border enzyme activities were similar. An enhanced gut trophic response to enteral feeding may help to improve postnatal intestinal adaptation and NEC resistance in preterm IUGR newborns. :

육계에 대한 복합 유기산제의 첨가급여 효과에 관한 연구

본 연구에서는 사료 내 복합 유기산제의 첨가급여가 육계 생산성, 맹장 미생물 균총, 혈액 특성 및 면역 활성에 미치는 영향을 조사하고 이를 통해 유기산의 성장촉진용 항생제 대체 가능성을 구명하고자 수행하였다. 1일령 육계 수평아리(Ross<TEX>$\times$</TEX>Ross 308) 480수를 공시하여 4처리, 4반복, 반복당 30수씩 배치하여 5주간 사양시험을 실시하였다. 시험구는 항생제 무첨가구, 항생제 첨가구(virginiamycin 10 ppm＋salinomycin 60 ppm)를 대조구로 하였으며, 시험사료에 유기산을 0.3% 및 0.5% 첨가하여 유기산 처리구를 두었다. 5주 종료체중, 증체량에 있어서 유기산 0.5% 처리구가 무항생제 처리구에 비해 유의하게 증가하였으며(P<0.05), 유기산 첨가 급여시 무항생제 처리구에 비해 사료 요구율이 유의하게 개선되었다(P<0.05). 도체율 및 조직의 상대적 중량에서는 처리구간 차이가 관찰되지 않았다. 소장 중량 및 길이는 항생제 첨가구가 다른 처리구에 비해 유의하게 감소하였으나(P<0.05), 유기산 처리구와 항생제 무첨가구간에는 차이가 없었다. 맹장 내 미생물 균총에 있어서 대조구인 항생제 첨가구와 유기산 처리구에서 맹장내 Coliform bacteria 및 Salmonella가 유의하게 감소하였으며 유산균에는 영향을 미치지 않았다. 혈액 내 총콜레스테롤, 중성지방, BUN, AST 및 ALT에 있어서는 통계적 유의성이 인정되지 않았다. Total protein 및 globulin 수치에 있어서는 항생제 첨가구 및 유기산 처리구가 항생제 무첨가구에 비해 유의하게 감소하였으며(P<0.05), albumin 수치에서는 차이가 없었다. 이로인해 항생제 첨가구 및 유기산 처리구의 혈청 내 albumin : globulin 비율이 항생제 무첨가구에 비해 유의하게 증가하는 결과를 보였다(P<0.05). WBC, heterophil, lymphocyte 및 스트레스 지표인 heterophil:lymphocyte 비율에 있어서 처리구간 차이가 관찰되지 않았으며, 비장 조직내 IL-2 및 IL-6 mRNA의 발현양상에 있어서도 유기산 첨가급여에 따른 변화는 관찰되지 않았다. 결론적으로 복합 유기산제의 육계 사료 내 첨가급여는 육계 생산성을 향상시키고, 유해균의 성장 및 증식을 억제하여 장내 미생물 균총의 안정화에 긍정적인 영향을 미치는 한편, 조직 발달 및 혈액 성상에 부정적인 영향을 미치지 않았다. This experiment was conducted to investigate the effects of dietary supplementation of organic acid mixture on growth performance, cecal microflora, blood characteristics and immune response in broiler chicks and to prove the possibility of organic acid mixture as an alternative to antibiotics growth promotor. A total of four hundred eighty, 1-day-old male broiler chicks (Ross<TEX>$\times$</TEX>Ross 308) were randomly divided into 4 groups with 4 replicates of 30 birds each. The treatments were NC (free antibiotics), PC (basal diet with virginiamycin 10 ppm and salinomycin 60 ppm), 0.3% organic acid, and 0.5% organic acid. The final body weight and body weight gain were significantly higher in organic acid 0.5% than NC (P<0.05). The feed conversion ratio in all treated groups were significantly improved as compared to that of NC (P<0.05). The carcass rate and relative organs weight were not significantly difference among the groups. The relative weight and length of small intestine in PC were significantly decreased than the other groups. The numbers of cecal coliform bacteria and Salmonella in all treated groups were significantly lower than NC (P<0.05). The number of cecal lactic acid bacteria was not different among the groups. No significant differences among the groups were observed in the contents of total cholesterol, triglyceride, blood urea nitrogen (BUN), albumin, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) in blood serum. The contents of total protein and globulin in blood serum of PC and organic acid treated groups were significantly increased as compared to those of NC (P<0.05). Therefore, albumin:globulin ratio of PC and organic acid treated groups was significantly lower than NC (P<0.05). The total white blood cell (WBC), heterophil, lymphocyte, and stress indicator (heterophil:lymphocyte ratio) were not significantly different among the groups. No significant difference was observed on the expression rate of splenic cytokines mRNA in organic acid treated groups compared to the control. Consequently, supplemental organic acid mixture improved the growth performance, and influenced positive effects on the intestinal microflora by inhibiting the growth of harmful bacteria without any adverse effects on relative weights of organs and blood biochemical parameters in broiler chicks.

Modifications of digestive enzymes in trout ( Oncorhynchus mykiss) and sea bream ( Sparus aurata) in response to dietary fish meal replacement by plant protein sources

Three experimental diets in which fish meal was partially (50 and 75%, named PP50 and PP75 diets, respectively) or totally replaced (PP100 diet) by plant protein sources were fed to rainbow trout and gilthead sea bream. We studied the effects of these diets on digestive enzymes in comparison to fish fed fish meal diets (FM). A mixture of vegetal ingredients (corn gluten meal, wheat gluten, extruded peas and rapeseed meal) was used to meet the amino acid requirements of the fish. Over a 12-week trial, four groups of the two species were fed one experimental diet twice a day until they showed satiety. After the growth period, post-prandial protease and α-amylase activities in proximal intestine were measured. Trout fed fish meal as the sole protein source (FM diet) showed a peak in total protease activity 3 h post-feeding; however, trout fed plant protein based diets (PP diets) did not register a peak in activity of these enzymes. In FM fed sea bream, proteolytic activity peaked in the most proximal intestinal segment 6 h post-feeding. This peak was also observed in PP fed sea bream, although the magnitude tended to decrease as the percentage of plant protein increased. This reduction was due to the specific inhibition of chymotrypsin-like bands, although a slight increase in trypsin secretion was detected in the zymograms of this species. The replacement of fish meal by plant protein did not affect α-amylase activity in either trout or sea bream. In sea bream proximal intestine histology was also studied. The PP100 fed group showed shorter folds and smaller goblet cell population when compared to FM fed group. In response to feeding the PP75 and PP100 diets, sea bream and trout showed a significant increase in relative intestinal length. Despite this compensatory mechanism, final weights of the two species diminished; however, this decrease exceeded 20% only in the case of groups fed the PP100 diets.

Effect of Grape Pomace Concentrate and Vitamin E on Digestibility of Polyphenols and Antioxidant Activity in Chickens

Grape pomace provides a rich source of polyphenols that have the capacity to act as powerful antioxidants. An experiment was conducted to study the effect of inclusion of grape pomace concentrate (GPC) at levels of 15, 30, and 60 g/kg and alpha-tocopheryl acetate (200 mg/kg) in broiler chicks (21 to 42 d of age) on performance; digestive organ sizes; protein; fat; hydrolyzable polyphenol and condensed tannin digestibilities; the anti-oxidant activity of diet, serum, ileal content, and excreta; and the susceptibility to oxidation of breast meat during refrigerated storage. The inclusion of GPC did not affect the performance; the apparent ileal digestibility of CP; the relative abdominal fat, liver, pancreas, and spleen weight; and the relative intestinal length. Fat digestibility was reduced in birds fed control and GPC diets compared with birds fed vitamin E. Ileal and fecal digestibility of hydrolyzable polyphenols and condensed tannins reached values in a range of 56 to 73% and 14 to 47%, respectively. The GPC diets reduced ileal and fecal digestibility of hydrolyzable polyphenols. Antioxidant activity in GPC diet, ileal content, and excreta [2, 2-azinobis (3-ethilenzotiazolin)-6-sulfonate method] and GPC diet (ferric antioxidant power method) exhibited higher scavenging free radical capacity than control and vitamin E diets. The lipid oxidation in breast meat was lower in the birds fed the supplemented vitamin E diet than the control diet after 1, 4, and 7 d of refrigerated storage. Oxidative stability in breast meat at 1, 4, and 7 d of storage was equivalent in GPC diets compared with the vitamin E diet. In conclusion, the inclusion of GPC (up to 60 g/kg) did not impair chicken growth performance, digestive organ sizes, and protein digestibility. Hydrolyzable polyphenols were more bioavailable than condensed tannins. Antioxidant activity in diet, excreta, ileal content, and breast muscle were increased in GPC diets. The GPC supplementation was equally as effective in antioxidant potential as vitamin E. On the basis of these observations, we concluded that GPC could be a new source of antioxidant in animal nutrition.

Effects of Different Dietary Levels of Mannanoligosaccharide on Growth Performance and Gut Development of Broiler Chickens

Different levels of dietary mannanoligosaccharide (Bio-MOS, Alltech Inc.) were evaluated for their efficacy on performance and gut development of broiler chickens during a 6-week experimental period. Experimental diets contained (g MOS/kg diet) a low (0.5 g during the entire period), medium (1 g during the entire period), high (2 g during the entire period), or step down (2 g in the first week; 1 g in the second and third week; 0.5 g in the last three weeks) level of MOS. Control diets included a negative and a positive control (zinc bacitracin, ZnB, 50 ppm and 30 ppm in the first and last three weeks, respectively). MOS supplementation improved the growth performance of young birds and the effects became less when the birds got older. The growth response of birds was more obvious at the high dosage level of MOS treatment than the other MOS treatments and the growth performance of birds fed on the high MOS diet was comparable to that of birds fed on the ZnB diet. Depending on the dosage level and the age of birds, MOS seemed to reduce the size of the liver and the relative length of the small intestine but did not affect the relative weight of the other visceral organs (proventriculus, gizzard, pancreas, bursa and spleen) and that of the small intestine. A numerical increase in the small intestine digestibility of nutrients was noticed in the young birds fed on the MOS diet(s), but not in the older ones. Medium and/or high MOS treatment also increased the villus height of the small intestine of birds at different ages. Similar results were observed on the ZnB treatment. However, MOS and ZnB affected caecal VFA profile in different ways. MOS increased, or tended to increase, whereas ZnB reduced individual VFA concentrations in the caeca.

Resource partitioning in a tropical stream fish assemblage

An assemblage of freshwater fishes inhabiting a medium‐sized stream in tropical central Vietnam was investigated with respect to spatial and trophic distribution. Point‐abundance sampling, gut content analysis and relative intestine length yielded interspecific differences in niche expression. Conspecific juvenile and adult habitat and feeding niches were also distinct. Niche differences arose mainly from differences in current velocity, substrata and foraging preferences. Extreme specializations, such as selective feeding on hard incustrations of cyanobacteria by adult Annamia normani, were present. The low niche overlap suggests that this tropical fish assemblage is structured by competitive interactions.