Dietary supplementation with a silicate clay mineral (palygorskite) alleviates inflammatory responses and intestinal barrier damage in broiler chickens challenged with Escherichia coli

This experiment aimed to explore the protective effects of dietary palygorskite (Pal) supplementation on inflammatory responses and intestinal barrier function of broiler chickens challenged with Escherichia coli (E. coli). A 2 × 2 factorial arrangement was designed to assess the effects of Pal administration (0 or 5 g/kg of feed) and E. coli challenge (E. coli or bacterial culture medium) on broilers in a 21-d feeding trial. Birds were randomly assigned into one of the 4 groups, and each group had 8 replicates with ten birds each. The challenged chickens were orally gavaged with E. coli suspended in Luria-Bertani broth on 14 d of age, while unchallenged birds were administrated with an equivalent amount of culture medium. The sampling was performed at 21 d of age. Compared with the normal birds, an oral E. coli challenge reduced final body weight, and decreased feed intake, weight gain, and feed efficiency during the challenge period (P < 0.05). E. coli challenge promoted colonization of E. coli in cecal content and their translocation to internal organs (heart, liver, and spleen) (P < 0.05). E. coli infection also increased levels of pro-inflammatory cytokines in jejunum and ileum possibly through activating the toll-like receptor-4-mediated signaling pathway (P < 0.05). Moreover, E. coli administration increased intestinal mucosal permeability (higher serum D-lactate level and diamine oxidase activity, and lower intestinal mucosal disaccharidase activities), altered intestinal morphology, and downregulated the gene expression of intestinal tight junction proteins (P < 0.05). In contrast, Pal supplementation enhanced growth performance, inhibited colonization of E. coli, reduced intestinal inflammation, decreased intestinal permeability, restored intestinal morphology, and normalized the expression of genes responsible for inflammatory processes and maintenance of intestinal mucosal barrier (P < 0.05), and most of these beneficial effects resulting from Pal administration were independent of bacterial challenge. The results indicated dietary Pal incorporation was effective in improving growth performance and alleviating inflammation and intestinal mucosal barrier damage in broilers challenged with E. coli.

Xylanase Supplement Enhances the Growth Performance of Broiler by Modulating Serum Metabolism, Intestinal Health, Short-Chain Fatty Acid Composition, and Microbiota

This study aimed to investigate the effects of different levels of xylanase supplementation in a wheat-based diet on growth performance, short-chain fatty acids, intestinal health, microbial composition, and serum metabolism. A total of 1200 male chicks were randomly assigned to four wheat-based diet treatments: Group C (adding 0 mg/kg of xylanase), Group L (adding 50 mg/kg of xylanase), Group M (adding 100 mg/kg of xylanase), and Group H (adding 150 mg/kg of xylanase). The experiment lasted for 56 days. The results indicated that Group H broilers experienced a decreased feed-to-gain ratio throughout the study period. Additionally, dietary supplementation with xylanase led to an increase in the physical barrier, as indicated by increased VH and VH/CD in the gut (p < 0.05). Furthermore, levels of D-lactic acid and endotoxin were reduced. Xylanase supplementation also increased the abundance of Muc-2, ZO-1, and Occludin (p < 0.05). Moreover, xylanase supplementation enhanced the activity of sucrase and maltase in the duodenum (p < 0.05), which may be attributable to the upregulation of the abundance of SI and MGA (p < 0.05). Furthermore, xylanase addition promoted propionic acid produced by specific bacteria, such as Phascolarctobacterium, and influenced the microbial composition to some extent, promoting intestinal health. Additionally, 150 mg/kg of xylanase supplementation increased the amino acid, peptide, and carbohydrate content and upregulated the metabolism of amino acids related to histidine, cysteine, methionine, and other pathways (p < 0.05). These findings suggest adequate xylanase supplementation can enhance nutritional digestibility and absorption, improve growth performance, stimulate endogenous enzyme activity, optimize intestinal morphology and barrier function, and positively influence acid-producing bacteria and amino acid metabolic pathways.

Supplementation of amylase or amylase + xylanase improves performance and metabolism of broilers fed with diets containing newly harvested maize

How supplementation with amylase or amylase + xylanase in newly harvested maize-based diets affects broiler nutrient metabolism and performance is unclear. Thus, this study evaluated whether the supplementation of amylase (CN) or amylase + xylanase (CAX) improves performance and metabolism of broilers fed with newly harvested maize-based diets during a 6-week production. The results showed that the body weight gain of broilers fed with CA or CAX diet was higher than that with the control (CN) diet at 1-21 d of age; however, an opposite trend was observed for feed/gain (p < 0.05). Furthermore, 150, 64 and 35 different metabolites were found between CA/CN, CAX/CN and CAX/CA, respectively. Overall, amylase supplementation improved broiler growth performance at 1-21 d of age, and the positive effects of amylase on nutrient utilization were mostly related to nicotinate, retinol and glutathione metabolism improvement. Moreover, CAX diet increased apparent metabolizable energy and growth performance of broilers at 22-42 d of age, and the difference might be related to sphingolipid, porphyrin and chlorophyll metabolism regulation. The findings prove amylase + xylanase supplementation is an effective method to improve the nutritional value of newly harvested maize for broilers.

The effect of amylase supplementation on individual variation, growth performance, and starch digestibility in broiler chickens

The objective of this study was to evaluate the variance of starch digestibility in broilers individually fed diets without or with supplemental exogenous amylase. A total of 120 d-of-hatch male chicks were individually reared from 5 to 42 d in metallic cages and fed maize-based basal diets or diets containing 80 kilo-novo-α-amylase units/kg (60 birds or replicates per treatment). Beginning on d 7, feed intake, body weight gain, and feed conversion ratio were recorded; partial excreta collection was conducted every Monday, Wednesday, and Friday until 42 d, when all birds were sacrificed for individual collection of duodenal and ileal digesta. Lower feed intake (4,675 vs. 4,815 g) and feed conversion ratio (1.470 vs. 1.508) were observed in amylase-fed broilers during the overall period (7-43 d; P < 0.01), whereas body weight gain was not affected. Amylase supplementation improved total tract starch (TTS) digestibility (P < 0.05) on each day of excreta collection (except for d 28, where no difference was found), averaging 0.982 vs. 0.973 compared to basal-fed broilers from d 7 to 42. Both apparent ileal starch (AIS) digestibility and apparent metabolizable energy (AME_N) were increased (P <0.05) from 0.968 to 0.976 and from 3,119 to 3,198 kcal/kg, respectively, with enzyme supplementation. Activity of amylase in the duodenum was higher (18.6 vs. 50.1 IU/g of digesta) in supplemented birds. Amylase supplementation led to a reduced coefficient of variation for both TTS (averaged 2.41 vs. 0.92% from 7 to 42 d) and AIS digestibilities (1.96 vs. 1.03%), as well as AME_N (0.49 vs. 0.35%), when compared to the nonsupplemented group, indicating lower individual heterogenity. An age effect was detected for TTS digestibility, as both groups saw an increase during the first weeks (slightly more pronounced in the supplemented group); older birds (d 30 onwards) presented a lower TTS digestibility compared to ages between 7 and 25 d. In conclusion, amylase supplementation in maize diets for broilers can attenuate individual bird variation for starch and energy utilization by increasing amylase activity and enhancing starch digestibility.

Supplemental Enzyme and Probiotics on the Growth Performance and Nutrient Digestibility of Broilers Fed with a Newly Harvested Corn Diet

A new grain phenomenon happens in newly harvested corn because of its high content of anti-nutritional factors (ANFs), which can cause low nutrient digestibility and diarrhea in animals. Enzymes and probiotics have been shown to relieve the negative effect of ANFs for animals. The purpose of this study was to investigate the effect of enzymes and probiotics on the performance and nutrient digestibility of broilers, fed with newly harvested corn diets. A total of 624 Arbor Acres Plus male broiler chickens were randomly divided into eight treatment groups (A: normal corn diet, CT: newly harvested corn diet, DE: newly harvested corn diet + glucoamylase, PT: newly harvested corn diet + protease, XL: newly harvested corn diet + xylanase, BCC: newly harvested corn diet + Pediococcus acidilactici BCC-1, DE + PT: newly harvested corn diet + glucoamylase + protease, XL + BCC: newly harvested corn diet + xylanase + Pediococcus acidilactici BCC-1). Each group was divided into six replicates, with 13 birds each. On day 21, growth performance, nutrient digestibility, and digestive enzyme activity were measured. Compared with the normal corn diet (PC), the newly harvested corn diet (NC) produced shorter digesta emptying time (p = 0.015) and increased visual fecal water content (p = 0.002) of broilers, however, there was no effect on performance. Compared to the newly harvested corn diet (NC), supplemental enzyme of DE increased the activity of chymotrypsin (p = 0.016), however, no differences in the digestibility of three kinds of organic matter, digesta emptying time, visual fecal water content, or performance were found. Supplemental protease (PT) significantly increased digesta emptying time (p = 0.004) and decreased the activity of maltase (p = 0.007). However, it had no effect on the digestibility of three kinds of organic matter or the performance of broilers. Supplemental xylanase (XL) decreased the activity of amylase (p = 0.006) and maltase (p < 0.001); however, it had no effect on digesta emptying time, visual fecal water content, the digestibility of three kinds of organic matter, or performance of broilers. Supplemental DE, combined with PT (DE + PT), increased the digesta emptying time (p = 0.016) while decreasing the visual fecal water content (p = 0.011), and the activity of amylase (p = 0.011), lipase (p = 0.021), and maltase (p < 0.001), however, there was no effect on performance. Supplemental BCC individually decreased the activity of amylase (p = 0.024) and maltase (p < 0.001), however, it increased the activity of trypsin (p < 0.001) and tended to improve feed conversion ratio (FCR) (p = 0.081). Supplemental BCC-1, combined with XL (XL + BCC), increased the activity of trypsin (p = 0.001) but decreased the activity of amylase (p = 0.013), lipase (p = 0.019), and maltase (p < 0.001). Pediococcus acidilactici BCC-1 (109 cfu/kg), protease (800,000 U/g) individually, or protease (800,000 U/g) in combination with glucoamylase (800,000 U/g) were supplemented in newly harvested corn diets for growing broilers. Hence, this study mainly explores the alleviation effect of enzyme and probiotics on the negative phenomenon caused by the utilization of newly harvested corn in broilers and provides a better solution for the utilization of newly harvested corn in production practice.

Deoxynivalenol damages the intestinal barrier and biota of the broiler chickens

Background

In the livestock feed industry, feed and feed raw materials are extremely susceptible to mycotoxin contamination. Deoxynivalenol (DON) is one of the main risk factors for mycotoxin contamination in broiler feed and feedstuff, however, there is still little knowledge about this. Hence, the purpose of this study was to explore the toxicity effect of DON on the intestinal barrier and the microecological balance of the biota in broiler chickens.

Results

In our present study, we compared the pathological scores of the small intestines of broilers on the 5^th, 7^th, and 10^th day, and chose the 7^th day to analyze the small intestine histomorphology, tight junctions, and cecal biota of the broilers. The results showed the damage to the small intestine worsened over time, the small intestinal villi of broilers were breakage, the tight junctions of the small intestine were destroyed, the cecal biota was unbalanced, and the growth performance of broilers was reduced on the 7^th day.

Conclusions

DON could damage the functional and structural completeness of the intestinal tract, disorder the Intestinal biota, and finally lead to declined broiler performance. Our study provided a basis for the prevention and treatment of DON in broiler production.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03392-4.

Effects of exogenous α-(1,4)-amylase on the utilisation of corn starch and glucose metabolism in broiler chickens

Starch is the most important energy source in corn-based diets for broiler chickens, however, some proportion of dietary starch may be partially digested, leading to a decrease in feed utilisation. Therefore, supplementing exogenous amylase might be a feasible way to improve the utilisation of dietary starch for poultry. This study investigated the effects of exogenous α-(1,4)-amylase supplementation on the utilisation of corn starch and glucose metabolism in broiler chickens. A total of 560, 4-d-old Arbour Acres plus male broiler chicks were randomly divided into five treatment groups and fed a corn-soybean meal diet supplemented with 0, 400, 600, 800 and 1 200 U/kg α-(1,4)-amylase to evaluate growth. The growth performance, nutrient digestibility coefficients, digestive enzyme activity, glucose transporter transcription and cecal microbiota composition were evaluated in this study. Starch digestibility coefficient showed a quadratic response to α-(1,4)-amylase at 14 d and 42 d (P < 0.05). However, the endogenous α-amylase activity in jejunal content was linearly decreased (P = 0.045). Also, exogenous α-(1,4)-amylase linearly decreased ileal Na+-dependent glucose and galactose transporter 1 mRNA expression at 42 d (P < 0.001). Exogenous α-(1,4)-amylase generated higher insulin and glucagon serum concentrations in fasted birds (P < 0.05) and following re-feeding for 2 h (P < 0.001). BW gain and feed intake were strongly positively correlated with starch digestibility coefficient at both 14 d (r = 0.87) and 42 d (r = 0.91); whereas, the relative weight of the gizzard was weakly negatively correlated with starch digestibility coefficient (r = -0.35). The relative abundance of Unclassified_Bacillaceae was moderately positively correlated (r > 0.50) while Oscillospira, Ornithobacterium and Unclassified_Barnesiellaceae were moderately negatively correlated (-0.50 < r -0.39) with starch digestibility coefficient. In conclusion, exogenous α-amylase modulates metabolic function by increasing insulin and glucagon concentrations, influenced gut microbiota which may impact starch digestibility in the jejunum and ileum. The results of this study showed that excessive addition of exogenous α-(1,4)-amylase was not beneficial for the utilisation of starch in broiler chickens. Supplement more than 600 U/kg α-(1,4)-amylase inhibited glucose transporters, decreases the coefficients of starch and organic matter digestibility in the small intestine to a varying degree, thereby limiting the growth performance of broiler chickens.

Effect of yeast cell wall supplementation on intestinal integrity, digestive enzyme activity and immune traits of broilers

1. The protective layer formed by intestinal epithelial cells acts as a barrier preventing the adhesion of pathogenic bacteria, aids digestion and passage of nutrients and reduces damage caused from toxins on the gastrointestinal tract. This study was conducted to investigate the effects of a yeast cell wall-based product (YCW), on broiler intestinal integrity, digestive enzyme capacity and immune function.2. A 35-d trial involving 246, one-d-of-hatch male broiler chickens was carried out at a trial facility at Agri-Food Biosciences Institute (AFBI, Belfast, UK). Birds were randomly allocated into 6 pens at day of hatch (41 birds/pen; 123 birds/group). Pens were divided into two groups: (1) basal diet and (2) basal diet that incorporated YCW at the manufacturers' recommended inclusion levels (Alltech Inc., Lexington, Kentucky, USA).3. In this study, YCW supplementation affected broiler intestinal morphology resulting in greater crypt depth, villus height and surface area, goblet cell density and mucus layer thickness and lower muscularis mucosae thickness. The digestive enzymes, maltase, sucrase and alkaline phosphatase, were significantly higher in the YCW supplemented group compared to the control. The expression levels of pro-inflammatory cytokines, IL-1β, IL-12 and IL-18, were significantly lower as was necroptotic cell death in YCW supplemented birds.4. In conclusion, under the conditions of this study, YCW supplementation positively affected intestinal health parameters in broilers following 35-d supplementation.

Different enzymatic associations in diets of broiler chickens formulated with corn dried at various temperatures

The effect of supplementation of different enzymatic associations in the feed of broiler chickens formulated with corn dried at 80°C or 110°C on growth performance and carcass yield was evaluated. In addition, the influence of the different enzymatic associations on the cecal microbiota was studied. One-day-old male broiler chicks (1,320) were distributed in a completely randomized design in a 2 × 5 factorial arrangement (6 replicates; 22 birds/replicate). The treatments were 2 corn drying temperatures (80°C and 110°C) and 5 diets. The diets consisted of a positive control (PC), a negative control (NC) with a reduction of 100 kcal/kg of apparent metabolizable energy, and 3 enzyme combinations added to the NC diet: amylase, amylase + xylanase, and amylase + xylanase + protease. The feed conversion ratio (FCR) from 1 to 7 d of chickens fed diets formulated with corn dried at 80°C was better (P = 0.045) than that of chickens fed diets dried at 110°C. Regardless of the enzymatic association, the supplementation improved body weight gain (P = 0.01) of the NC group to the same level as the PC group. The FCR of the NC was similar to that of the PC only when the 3 enzymes were included from 1 to 21 d (P = 0.001) and regardless of the enzymatic association for the period from 1 to 42 d (P = 0.007). Regarding cecal microbiota, the alpha diversity was similar among the groups (P > 0.05). The beta-diversity analysis showed that the microbiota of the birds receiving the combination of the 3 enzymes was similar to that of birds fed the PC diet (P = 0.18; R = 0.074), with a similar effect observed for the predicted metabolic functions (Linear discriminant analysis effect size). In conclusion, chickens fed diets formulated with corn dried at 80°C had better FCR during the prestarter phase. The enzymatic supplementation improved the FCR of the birds, which may partially be explained by the modulation of the cecal microbiota.

Exogenous α-amylase improves the digestibility of corn and corn-soybean meal diets for broilers

Starch is the main energy source in broiler diets. However, endogenous amylase secretion in young broilers is suboptimal to completely digest dietary starch, so exogenous α-amylase supplementation may help increase starch digestibility. The objective of this study was to assess the supplementation of increasing doses of an exogenous α-amylase (0, 40, 80, 120, and 160 kilo-novo α-amylase units (KNU)/kg) on corn and on a complete corn-soybean meal diet for 25-day-old broilers. Jejunal and ileal apparent digestibility coefficients of available starch, resistant starch, total starch, and DM, DM total tract retention, as well as dietary AME levels were evaluated. Interactions (P < 0.05) between diets and α-amylase showed that the enzyme had a more evident effect on increasing DM jejunal digestibility and AME on corn compared with the complete diet. Corn DM digestibility increased to a maximum of 67.84% with up to 47 KNU/kg, whereas 89 KNU/kg led to a maximum of 53.92% in the complete diet A maximum increase of 64 kcal AME/kg was obtained with 80 KNU/kg on the complete diet, whereas 109 KNU/kg generated 327 kcal AME/kg on corn (P < 0.05). Increasing the α-amylase dose linearly increased ileal digestibility of resistant starch (P < 0.05), and the effect on DM total tract retention was quadratic (P < 0.05). Corn showed a higher digestibility for DM, resistant and total starch, as well as DM total tract retention and AME, compared with the complete diet (P < 0.05). Treatments had no influence on available starch. The inclusion of exogenous α-amylase improves starch, DM, and energy utilization of corn-based and corn-soybean meal-based diets for broilers.

Polymorphisms of AMY1A gene and their association with growth, carcass traits and feed intake efficiency in chickens

Investigations on the association between chicken traits and genetic variations can provide basic information to improve production performance in chickens. In our previous work, we genotyped 450 male chickens with a 600 K SNP array [1] and found that several SNPs in the genomic regions of the amylase alpha 1A (AMY1A) gene were significantly associated with feed intake efficiency and carcass traits. Given the lower accuracy of the SNP array, we performed direct sequencing with male and female chickens to further test chicken AMY1A polymorphisms and investigate their association with 17 traits in chickens. The results showed that 7 SNPs in the 5' flanking region, exon, intron and 3' UTR (3' untranslated region) of AMY1A, were significantly associated with daily gain (DG), average daily feed intake (ADFI), leg muscle weight (LMW) and abdominal fat (AF) (p < 0.05). Additionally, the haplotypes based on three SNPs, rs15910189, rs314354067 and rs316026696, showed significant associations with DG (p < 0.01), ADFI and AF (p < 0.05). To better understand the transcriptional regulation of AMY1A, we cloned its 5' flanking region and found that the SNPs rs316436216 and rs314213090 which might change the transcriptional regulator binding sites, were in the suppressor and enhancer regions, respectively. In addition, luciferase assays revealed that the SNP rs314613110 in the 3' UTR influenced the binding of the miRNA gga-miR-1764-3p. To validate whether there is any copy number variation in AMY1A in our population, we performed a genome-wide assessment of CNVs through whole-genome resequencing data. However, no CNV was found in AMY1A in our population, which is different from the increased copy number of AMY1A found in humans who consume a high-starch diet. Therefore, the present study provides substantial evidence for the association of AMY1A polymorphisms with growth traits and feed intake efficiency, which might contribute to chicken breeding programs.

Intestinal starch and energy digestibility in broiler chickens fed diets supplemented with α-amylase

Dietary starch is the major energy source for broiler chickens; therefore, relevant information on its intestinal utilization is important. The present study was designed to evaluate intestinal starch and energy digestibility of broiler chickens fed diets supplemented with α-amylase. A total of 240 day-0 male broiler chicks were randomly assigned to 3 nutritionally adequate corn-soybean-based experimental diets comprising 3 levels of α-amylase supplementation (0, 80, or 160 KNU/kg diet). Each treatment comprised 8 replicate cages of 10 birds each. At day 21 after hatching, digesta was collected from 4 intestinal sites: the anterior jejunum (AJ), posterior jejunum (PJ), anterior ileum (AI), and posterior ileum. Increasing α-amylase supplementation linearly improved (P < 0.01) overall BW gain and feed efficiency of the birds. There were linear and quadratic (P < 0.01) responses of increasing α-amylase supplementation on starch and energy digestibility at the PJ and AI. The total tract digestibility of starch increased (P < 0.05) with increasing α-amylase supplementation. Starch disappearance and digestible energy (kcal/kg) linearly increased (P < 0.01) with digesta flow from the AJ to PJ as dietary α-amylase supplementation increased. There were linear (P < 0.01) and quadratic (P < 0.05) effects of increasing α-amylase supplementation on the villus height in the jejunum. The viscosity of the jejunal digesta decreased (P < 0.05) with increasing dietary α-amylase supplementation. The results from this study showed the efficacy of exogenous amylase in improving growth performance and starch and energy digestibility in broiler chickens. Furthermore, the digestibility of starch and energy and the impact of the exogenous amylase were higher at the PJ than other intestinal sites.

Effects of dietary amylose/amylopectin ratio and amylase on growth performance, energy and starch digestibility, and digestive enzymes in broilers

This study was conducted to investigate the effects of dietary amylose/amylopectin (AM/AP) ratio and amylase on growth performance, apparent digestibility of energy and starch, serum biochemical index, and digestive enzymes. The experiment used a 4 × 3 factor design, and 960 one-day-old Arbor Acres (AA) broilers were randomly divided into 12 groups fed diets containing different AM/AP ratio of 0.11, 0.23, 0.35 and 0.47 and combined with 0, 3,000 and 6,000 U/kg amylase. Results showed that 0.23-0.35 AM/AP ratio increased growth performance, while dietary addition of 6,000 U/kg amylase significantly reduced average daily weight gain in broilers. The energy digestibility was significantly reduced along with the increase of dietary AM/AP ratio and in the 6,000 U/Kg amylase-supplemented groups. The digestibility of starch also decreased significantly with the increase of dietary AM/AP ratio, but high dose (6,000 U/Kg) of amylase increased. High AM/AP diet reduced serum insulin concentration, which was increased in amylase-supplemented groups. Furthermore, exogenous amylase increased amylase activity in the jejunal chyme. In conclusion, dietary 0.23-0.35 AM/AP ratio was suggested to maintain a higher growth performance in broilers and high AM/AP ratio diets reduced energy and starch digestibility and serum insulin concentration, which was reversed by dietary amylase.

Effect of different levels of supplementary alpha-amylase in finishing broilers

The objective of this study was to investigate the effects of alpha-amylase supplementation on performance and carcass and cuts yield in broilers during finishing phase (21 to 42 days). A completely randomized experimental design with six treatments and eight replications was used: Positive Control (PC): no enzyme; Negative control (NC): without enzyme formulated with 6.34% less energy (- 6.34% ME); NC1: with 250 g ton-1 of alpha-amylase; NC2: with 500 g ton-1 of alpha-amylase; NC3: with 750 g ton-1 of alpha-amylase; NC4: with 1000 g ton-1 of alpha-amylase. Significant differences in weight gain, feed intake and feed conversion were reported with the inclusion of alpha-amylase. The NC treatment with inclusion of amylase provided improvement values of weight gain, feed conversion and feed intake, but do not was similarly in comparison to those obtained in broilers fed a diet that completely met the requirements during this phase. There was no dietary influence on carcass parameters. The use of alpha-amylase was effective in improving performance in broilers fed a diet of 200 kcal kg-1 of reduced metabolizable energy.

Effects of different starch sources on glucose and fat metabolism in broiler chickens

1. The aim of the present study was to investigate the effects of different starch sources (corn, wheat, and rice) on the blood glucose level, glycogen content of liver and muscle, expression of GSK-3β and FAS mRNA, abdominal fat weight and abdominal fat deposition in broiler chickens. 2. A total of 360, one-day-old AA (Arbor Acres) broiler chickens were randomly assigned to three treatment groups, each with six replicates, consisting of 20 chickens per replicate, and fed either a corn-, wheat- or rice-based diet for 21 days. The chickens were then subdivided into groups A and B, and the chickens in these two subgroups were processed or sampled for 28 days, respectively. 3. The results indicated that post-prandial time significantly affected the glucose concentration, glycogen content in the liver and breast muscle and expression of GSK-3β and FAS mRNAs (P < 0.05). The expression of the GSK-3β gene in the chicken liver of the corn-based diet group was higher (P < 0.05) than that in the wheat-based diet group, and the expression of the FAS gene in the corn-based diet group was lower (P < 0.05) than that in the wheat-based and rice-based diet groups. Abdominal fat weight and deposition in the corn-based diet group were lower than those of the wheat-based and rice-based diet groups, but these differences were not significant (P > 0.05). 4. The results suggested that the efficiency of glucose absorption in animals might have an effect on the fat deposition efficiency in the liver and that diets with different starch sources might affect fat deposition in chickens.

Prececal amino acid digestibility of soybean cake in fast- and slow-growing broiler chickens

The objective of the present study was to determine whether there are differences in prececal amino acid digestibility between commonly used slow- and fast-growing broiler strains when the regression approach is applied. ISA J-275 and Ross 308 were selected as common representatives of slow- and fast-growing broiler strains, respectively. The experimental diets with soybean cake at levels of 0, 100, and 200 g/kg were offered for ad libitum consumption between 22 and 29 d post-hatch. Titanium dioxide was used as an indigestible marker. Each treatment was tested with six pens comprising 10 birds each. Digesta samples were collected on a pen basis from the distal two-thirds of the intestine section between Meckel's diverticulum and 2 cm anterior to the ileocecal-colonic junction. The prececal amino acid digestibility of soybean cake was calculated by linear regression simultaneously for both strains. There was no significant interaction between broiler strain and inclusion level of soybean cake with respect to the prececal CP and amino acid digestibility of complete diets; there was a significant strain effect for 5 out of the 16 measured amino acids. The prececal CP and amino acid digestibility of soybean cake did not differ significantly between strains and was numerically almost identical. The results of the present study provide evidence of the transferability between broiler strains of prececal amino acid digestibility data, determined using the regression approach, thus improving the accuracy of diet formulation without drawbacks.