Comparative characterization of bacterial communities in geese fed all-grass or high-grain diets

Inclusion of Tenebrio molitor larvae meal in the diet of barbary partridge (Alectoris barbara) improves caecal bacterial diversity and composition

In this study, we investigated the influence of the inclusion of Tenebrio molitor (TM) larvae meal in the diet on the diversity and structure of the bacterial community in the caecal content of Barbary partridges. A total of 36 partridges, selected randomly for slaughter from 54 animals, were divided equally into three treatment groups, including the control group (C) with a diet containing corn-soybean meal and two experimental groups, in which 25% (TM25) and 50% (TM50) of the soybean meal protein was replaced by the meal from TM larvae. After slaughtering, the bacterial community of the 30 caecal samples (10 samples per each experimental group) was analysed by high-throughput sequencing using the V4-V5 region of the 16 S rRNA gene. Alpha diversity showed a higher diversity richness in the TM50 group. Beta diversity showed statistical dissimilarities among the three groups. Firmicutes was the dominant phylum regardless of the diet, with the predominant families Ruminococcaceae and Lachnospiraceae. Clostridia and Faecalibacterium were decreased in both TM groups, Lachnospiraceae was suppressed in the TM50 group, but still this class, genus and family were abundantly present in all samples. Several potentially beneficial genera, such as Bacillus, Ruminococcaceae UCG-009, Oscillibacter and UC1-2E3 (Lachnospiraceae) were increased in the TM50 group. The results showed a beneficial effect of the T. molitor larvae meal on the caecal microbiota of Barbary partridges, particularly in the TM50 group, which showed an increase in bacterial diversity.

Lactiplantibacillus sp. G6 isolated from goose intestine as starter culture for degrading nitrite and improving quality in Chinese pickle fermentation

Animal intestines is considered as a source of lactic acid bacteria (LAB) that have potential to decrease the nitrite level during fermentation of food such as pickles. It was hypothesized that optimized level of LAB has a high capacity to degrade nitrite during Chinese pickle fermentation and benefit a higher acceptability of the Chinese pickle product. This study aims to investigate the performance of a goose intestine-isolated LAB strain G6 under the species Lactiplantibacillus plantarum as a starter culture of Chinese pickles. The results showed that Lactiplantibacillus sp. G6 had a nitrite degradation rate close to 100% under the MRS broth condition of 25 °C, 2% inoculum volume and pH at 5. As a starter culture for Chinese pickle, this strain was able to achieve a higher LABs amount, lower nitrite residue after fermentation, compared with the group without the starter, which implicates its feasibility of applying on fermented food for reducing nitrite level.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01433-8.

Effects of fermented feed on growth performance, serum biochemical indexes, antioxidant capacity, and intestinal health of lion-head goslings

Introduction

The aim of this study was to evaluate the effects of fermented feed on growth performance, antioxidant indexes and intestinal health in lion-head goslings.

Methods

288 male lion-head goslings (one-day-old) were randomly divided into four groups (6 replicates per group, 12 samples per replicate): control group (basal diet) and fermented feed (FF) groups (basal diet supplemented with 2.5, 5.0 and 7.5% FF, respectively). The experimental period lasted 28 days.

Results

The results showed that 5.0 and 7.5% FF groups decreased feed conversion rate (FCR) when compared with the control group (p < 0.05). The 5.0% FF group reduced the activity of alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) in serum; while the 7.5% FF group decreased the concentration of total cholesterol (TC), ALP and LDH activity (p < 0.05). Furthermore, the 7.5% FF group significantly increased total antioxidant capacity (T-AOC) in serum (p < 0.05); 2.5% and 5.0% FF groups significantly increased glutathione peroxidase (GSH-Px) in serum (p < 0.05); all FF groups increased the activity of superoxide dismutase (T-SOD) in serum (p < 0.05). For intestinal health, the villous height and villi/crypt ratio in jejunum were increased in all FF groups, but crypt depth was decreased (p < 0.05); The 5.0% FF groups enhanced T-AOC activity in jejunum (p < 0.05); The 2.5% and 5.0% FF groups enhanced GSH-Px activity (p < 0.05) in jejunum; All FF groups reduced malondialdehyde (MDA) level in jejunum (p < 0.05). LEfSe analysis showed that the cecum microbiota was significantly dominant in the 2.5% FF group compared to the control group including Firmicutes, Lactobacillales, Lactobacillus, and Prevotella; the flora that were significantly dominant in the 5.0% FF group compared to the control group included Bacteroidaceae, Bacteroides, Megamonas, and Prevotella; and the groups that were significantly dominant in the 7.5% FF group compared to the control group included Bacteroidota, Bacteroides, Bacteroidaceae, and Ruminococcaceae.

Discussion

In summary, dietary FF supplementation improved growth performance, serum biochemical parameters and antioxidant capacity of lion-head goslings, as well as improved jejunal tissue morphology and optimized intestinal flora structure. In particular, the FF addition at a dose of 7.5% was relatively more effective for lion- head goslings.

Feeding whole-plant ensiled corn stover affects growth performance, blood parameters, and Cecal microbiota of Holdobagy goose

Introduction

The aim of this study was to investigate the effects of adding whole-plant ensiled corn stalks (WECS) to the diet of Holdorbagy geese on their growth performance, serum parameters, and cecal microbiota. Geese farming is an important agricultural practice, and optimizing their diet can contribute to better growth and health outcomes. However, there is limited research on the utilization of WECS as a feed source for geese. Understanding the potential effects of WECS on growth, blood parameters, and cecal microbiota can provide valuable insights into its feasibility and impact on geese farming practices.

Methods

A total of 144 six-week-old Holdorbagy geese were randomly assigned to one of three groups: a control group (0% WECS), a group fed 15% WECS and 85% concentrated feed (15% WECS), and a group fed 30% WECS and 70% concentrated feed (30% WECS). The trial period lasted for three weeks, during which the growth performance, serum parameters, and cecal microbiota were assessed.

Results

The results revealed significant findings in different aspects. Firstly, the feed-to-gain ratio (F/G ratio) of the 15% WECS group was significantly higher than that of the control group (p<0.05), indicating potential challenges in feed efficiency. Additionally, the average daily feed intake (ADFI) of both the 15% and 30% WECS groups was significantly higher than that of the control group (p<0.05), suggesting increased appetite or palatability of the diet containing WECS. In terms of serum parameters, the level of lactate dehydrogenase (LDH) in the 30% WECS group was significantly lower than that in the control group (p<0.05). Moreover, there was a tendency for increasing Fe levels and decreasing Zn levels with higher levels of WECS supplementation, although the differences were not statistically significant (p<0.05). Furthermore, the principal coordinate analysis showed significant differences in the composition of cecal microbiota among the three groups (p < 0.01). The observed_species, Shannon, and Pielou_e indices of the 30% WECS group were significantly higher than those of the 0% and 15% WECS groups (p<0.05), while the Simpson index of the 15% WECS group was significantly lower than that of the control group (p<0.05).

Discussion

The results indicate that the addition of WECS to the geese diet has both positive and negative effects. The study suggests that WECS can be a long-term stable feed source for geese, which can contribute to reducing feeding costs. However, it is important to monitor the amount of WECS added as it can affect the absorption of Zn by geese. Supplementation of Zn in the diet might be necessary to meet the needs of geese. Notably, adding 30% WECS to the diet can increase the richness, evenness, and diversity of the cecal microbiota, indicating potential benefits to gut health. In conclusion, this study highlights the potential of WECS as a feed source for geese. It provides valuable insights into the effects of WECS on growth performance, serum parameters, and cecal microbiota. These findings contribute to optimizing geese farming practices, improving feed utilization, and enhancing overall productivity and well-being of geese. Further research is needed to determine the optimal inclusion level of WECS and to explore strategies for mitigating any negative effects.

Key Aroma Compounds in Roasted White Kołuda Goose

Aroma-active compounds in the roasted leg meat of White Kołuda goose were assayed by gas chromatography-olfactometry, using aroma extract dilution analysis and solvent-assisted flavor evaporation. Quantitation, recombination-omission tests, and sensory evaluation were carried out. Thirty aroma compounds, for which odor activity values (OAVs) were calculated and for which the flavor dilution factors were greater than or equal to 1, were identified. The concentration of aroma compounds ranged from 0.06 to 633 (μg/kg). The highest OAVs (>1024) were for 2-furfurylthiol, 2-acetyl-1-pyrroline, and 1-octen-3-one. Nine key aroma compounds were: 2-furfurylthiol, 2-acetyl-2-thiazoline, 1-octen-3-one, 2-phenylethanethiol, 4,5-dimethyl-3-hydroxy-2(5H)-furanone, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, (E,E)-2,4-decadienal, 2-acetyl-1-pyrroline, and 3-(methylthio)propanal. The intensity of the dominating roasted, meaty/broth, and fatty notes in the recombination model consisting of the key odorants were rated (10-point scale) at 4.6-5.8 points, relative to the original roasted goose (5.2-6.2). The aroma compounds defined predominantly the meaty, roasted, and fatty flavors during the descriptive sensory evaluation of the roasted goose meat.

Enzyme-Treated Soybean Meal Replacing Extruded Full-Fat Soybean Affects Nitrogen Digestibility, Cecal Fermentation Characteristics and Bacterial Community of Newly Weaned Piglets

The study investigated the impact of soybean protein from different processing on the performance, dietary nitrogen digestibility, cecal fermentation characteristics, and bacterial community in newly weaned piglets. The piglets were allocated to two dietary treatment and fed with the extruded full-fat soybean diet (EFS group) and enzyme-treated soybean meal diet (ESBM group), respectively. The piglets in ESBM group showed greater nitrogen digestibility and feed efficiency, and lower diarrhea rate in comparison to piglets in EFS group (P < 0.05). Cecal samples from piglets in ESBM group contained greater concentration of acetate, propionate and total SCFAs (P < 0.05), and lower contents of isobutyrate, isovalerate, total BCFAs, NH₃-N and putrescine (P < 0.05) than cecal samples from piglets in the EFS group. The cecal samples from piglets in ESBM group contained greater abundances of g_Blautia, g_Coprococcus_3, g_Fusicatenibacter, and g_Bifidobacterium than the cecal sample from piglets in the EFS group, which could promote to protect intestinal health. In summary, enzyme-treated soybean meal may enhance the growth performance of weaned piglets via increasing the dietary nitrogen digestibility, preventing protein fermentation in the hindgut, which shed light on the mechanism in regulating gut health of dietary protein.

The intestinal microbial composition in Greylag geese differs with steatosis induction mode: spontaneous or induced by overfeeding

Background

Relationships between microbial composition and steatosis are being extensively studied in mammals, and causal relations have been evidenced. In migratory birds the liver can transiently store lipids during pre-migratory and migratory phases, but little is known about the implications of the digestive microbiota in those mechanisms. The Landaise greylag goose (Anser anser) is a good model to study steatosis in migratory birds as it is domesticated, but is still, from a genetic point of view, close to its wild migratory ancestor. It also has a great ingestion capacity and a good predisposition for hepatic steatosis, whether spontaneous or induced by conventional overfeeding. The conventional (overfeeding) and alternative (spontaneous steatosis induction) systems differ considerably in duration and feed intake level and previous studies have shown that aptitudes to spontaneous steatosis are very variable. The present study thus aimed to address two issues: (i) evaluate whether microbial composition differs with steatosis-inducing mode; (ii) elucidate whether a digestive microbial signature could be associated with variable aptitudes to spontaneous liver steatosis.

Results

Performances, biochemical composition of the livers and microbiota differed considerably in response to steatosis stimulation. We namely identified the genus Romboutsia to be overrepresented in birds developing a spontaneous steatosis in comparison to those submitted to conventional overfeeding while the genera Ralstonia, Variovorax and Sphingomonas were underrepresented only in birds that did not develop a spontaneous steatosis compared to conventionally overfed ones, birds developing a spontaneous steatosis having intermediate values. Secondly, no overall differences in microbial composition were evidenced in association with variable aptitudes to spontaneous steatosis, although one OTU, belonging to the Lactobacillus genus, was overrepresented in birds having developed a spontaneous steatosis compared to those that had not.

Conclusions

Our study is the first to evaluate the intestinal microbial composition in association with steatosis, whether spontaneous or induced by overfeeding, in geese. Steatosis induction modes were associated with distinct digestive microbial compositions. However, unlike what can be observed in mammals, no clear microbial signature associated with spontaneous steatosis level was identified.

Characterization of Metagenome-Assembled Genomes and Carbohydrate-Degrading Genes in the Gut Microbiota of Tibetan Pig

Tibetan pig is an important domestic mammal, providing products of high nutritional value for millions of people living in the Qinghai-Tibet Plateau. The genomes of mammalian gut microbiota encode a large number of carbohydrate-active enzymes, which are essential for the digestion of complex polysaccharides through fermentation. However, the current understanding of microbial degradation of dietary carbohydrates in the Tibetan pig gut is limited. In this study, we produced approximately 145 gigabases of metagenomic sequence data for the fecal samples from 11 Tibetan pigs. De novo assembly and binning recovered 322 metagenome-assembled genomes taxonomically assigned to 11 bacterial phyla and two archaeal phyla. Of these genomes, 191 represented the uncultivated microbes derived from novel prokaryotic taxa. Twenty-three genomes were identified as metagenomic biomarkers that were significantly abundant in the gut ecosystem of Tibetan pigs compared to the other low-altitude relatives. Further, over 13,000 carbohydrate-degrading genes were identified, and these genes were more abundant in some of the genomes within the five principal phyla: Firmicutes, Bacteroidetes, Spirochaetota, Verrucomicrobiota, and Fibrobacterota. Particularly, three genomes representing the uncultivated Verrucomicrobiota encode the most abundant degradative enzymes in the fecal microbiota of Tibetan pigs. These findings should substantially increase the phylogenetic diversity of specific taxonomic clades in the microbial tree of life and provide an expanded repertoire of biomass-degrading genes for future application to microbial production of industrial enzymes.

Fermented Feed Supplement Relieves Caecal Microbiota Dysbiosis and Kidney Injury Caused by High-Protein Diet in the Development of Gosling Gout

Firstly, forty-eight 1-day-old goslings were randomly allocated to four groups and were fed diets containing crude protein (CP) at different concentrations: 160, 180, 200, and 220 g/kg in Experiment One. We found a dose-dependent relationship between the dietary protein levels and morbidity of gosling gout. The concentration of serum uric acid (UA), creatinine (Cr), and urea nitrogen (UN), and the activity of xanthine oxidase in the 220CP groups were significantly higher than those in the low-protein diet groups. Beneficial microbes, including Akkermansia, Lactococcus, and Butyricicoccus were enriched in the ceca of healthy goslings, while the microbes Enterococcus, Enterobacteriaceae, and Bacteroides were enriched in those with gout. Then, we explored the effects of fermented feed on gosling gout caused by high-protein diets in Experiment Two. A total of 720 1-day-old goslings were randomly allotted to four experimental groups: CN (162.9 g/kg CP), CNF (167.5 g/kg CP, replacing 50 g/kg of the basal diet with fermented feed), HP (229.7 g/kg CP, a high-protein diet), and HPF (230.7 g/kg CP, replacing 50 g/kg of the high-protein diet with fermented feed). We found that the cumulative incidence of gout increased in the HP group compared with that in the control, but decreased in the HPF group compared to that in the HP group. Similarly, the concentration of serum UA in the HP group was higher than that in the CN group, but decreased in the HPF group. Meanwhile, compared with the HP group, using fermented feed in diets decreased the abundance of Enterococcus in the ceca of goslings, while increasing the abundance of Lactobacillus. These results suggest that appropriate dietary protein levels and the fermented feed supplement might relieve the kidney injury and gut microbiota dysbiosis caused by high-protein diets in the development of gosling gout.

Exploring the effect of plant substrates on bacterial community structure in termite fungus-combs

Fungus-cultivating termites are successful herbivores largely rely on the external symbiotic fungus-combs to decompose plant polysaccharides. The comb harbors both fungi and bacteria. However, the complementary roles and functions of the bacteria are out of the box. To this purpose, we look into different decomposition stages of fungus-combs using high-throughput sequencing of the 16S rRNA gene to examine bacterial community structure. We also explored the bacterial response to physicochemical indexes (such as moisture, ash content and organic matter) and plant substrates (leaves or branches or mix food). Some specific families such as Lachnospiraceae, Ruminococcaceae, and Peptostreptococcaceae may be involved in lignocellulose degradation, whereas Burkholderiaceae may be associated with aromatic compounds degradation. We observed that as the comb mature there is a shift of community composition which may be an adjustment of specific bacteria to deal with different lignocellulosic material. Our results indicated that threshold amount of physicochemical indexes are beneficial for bacterial diversity but too high moisture, low organic matter and high ash content may reduce their diversity. Furthermore, the average highest bacterial diversity was recorded from the comb built by branches followed by mix food and leaves. Besides, this study could help in the use of bacteria from the comb of fungus-cultivating termites in forestry and agricultural residues making them easier to digest as fodder.

Fermented feed regulates growth performance and the cecal microbiota community in geese

This study was designed to investigate the effects of fermented feed diets on the growth performance and cecal microbial community in geese, and to examine associations between the gut microbiota and growth performance. A total of 720 healthy, 1-day-old male SanHua geese were used for the 55-D experiment. Geese were randomly divided into 4 groups, each with 6 replicates of 30 geese. Groups were fed a basal diet supplemented with 0.0, 2.5, 5.0, or 7.5% fermented feed. The results showed that 7.5% fermented feed had an increasing trend in the body weight and average daily gain of the geese; however, there was no significant response to increasing dietary fermented feed level with regards to ADFI and FCR. In addition, compared with the control group, there was a higher abundance of bacteria in the phylum Bacteroidetes in the cecal samples of geese in the 7.5% fermented feed group (53.18% vs. 41.77%, P < 0.05), whereas the abundance of Firmicutes was lower in the 7.5% fermented feed group (36.30% vs. 44.13%, P > 0.05). At the genus level, the abundance of Bacteroides was increased by adding fermented feed to geese diets, whereas the abundances of Desulfovibrio, Phascolarctobacterium, Lachnospiraceae_uncultured, Ruminiclostridium, and Oscillospira were decreased. These results indicate that fermented feeds have an important effect on the cecal microflora composition of geese, and may affect host growth, nutritional status, and intestinal health.

Comparative study on the effects of different feeding habits and diets on intestinal microbiota in Acipenser baeri Brandt and Huso huso

Background

Siberian sturgeon (Acipenser baeri Brandt) and Beluga sturgeon (Huso huso) are two important commercial fish in China, and the feeding habits of them are very different. Diets and feeding habits are two significant factors to affect the gastrointestinal microbiota in fish. The intestinal microbiota has been reported to play a key role in nutrition and immunity. However, it is rarely reported about the relationship between the intestinal microbiota and feeding habits/diets on different Acipenseridae fish. This study is to comparative analysis of gut microbial community in Siberian sturgeon and Beluga sturgeon fed with the same diet/Beluga sturgeon fed with different diets in order to determine the effects of different feeding habits/diets on the fish intestinal microbiota.

Results

According to the experimental objectives, BL and BH groups were Beluga sturgeon (Huso huso) fed with low fishmeal diet and high fishmeal diet, respectively. SH group represented Siberian sturgeon (Acipenser baeri Brandt) fed with the same diet as BH group. After 16 weeks feeding trial, the intestinal microbiota was examined by 16S rRNA high-throughput sequencing technology. On the phylum level, Proteobacteria and Bacteroidetes were significantly higher in BL group than BH group, and Cyanobacteria showed the opposite trend. Compared with BH group, Proteobacteria and Firmicutes were significantly increased in SH group, whereas Cyanobacteria were clearly decreased. At the genus level, Pseudomonas and Citrobacter in BL group were significantly higher comparing with BH group, while Bacillus, Luteibacter, Staphylococcus and Oceanobacillus was lower in BH group than SH group.

Conclusions

Alpha and beta diversities indicated that the intestinal microflora were significant difference between Siberian sturgeon and Beluga sturgeon when they fed with the same diet. Meanwhile, Beluga sturgeon fed with low fishmeal diet can increase the species diversity of intestinal microbiota than it fed high fishmeal diet. Therefore, feeding habits clearly affected the gastrointestinal microbiota of sturgeons. Moreover, the impact of changes in food on the gut microbiota of sturgeons should be taken into consideration during the process of sturgeon aquaculture.

Comparative characterization of bacterial communities in geese consuming of different proportions of ryegrass

Geese are extremely well-adapted to utilizing plant-derived roughage in their diet, so the grass must be added to commercial diets under intensive rearing systems. However, it is unclear whether the gut microbiota will change significantly when adding different proportions of ryegrass. In this study, 240 healthy male Yangzhou geese (28 days old) with similar body weights were randomly divided into four groups and fed different proportions grass (CK, whole commercial diets; EG1, ryegrass: commercial diets = 1.5:1; EG2, ryegrass: commercial diets = 2:1; EG3, ryegrass: commercial diets = 3:1) respectively. When the geese grew to 70 days old, their intestines were collected and high-throughput sequencing technology was performed to investigate the microbial diversity in the caecum of geese with different dietary supplements. There was no obvious change in the alpha diversity of gut microbiota of geese with ryegrass intake (P > 0.05) and the composition of dominant bacterium (including Bacteroidetes and Firmicutes) was also similar. However, the ratio between Firmicutes and Bacteroidetes was remarkably reduced with ryegrass intake (P < 0.05), and the relative abundance of 30 operational taxonomic units (OTUs) significantly differed. Additionally, the content of cellulose-degrading microbiota such as Ruminiclostridium and Ruminococcaceae UCG-010 were significantly increased in geese fed with increasing amounts of grass. Finally, the functional profiles of the goose gut microbiota were explored using the PICRUSt tool. Carbohydrate metabolism and amino acid metabolism were dominant metabolic pathways. Lipid metabolism was significantly increased in EG3 compared that in the CK group (P < 0.05). Interestingly, Turicibacter and Parasutterella may have affected abdominal fat deposition as grass intake increased. Taken together, although the diversity of bacterial communities was similar in geese fed with different proportions of ryegrass, cellulose-degrading microbiota (Ruminiclostridium and Ruminococcaceae UCG-010) were abundant and the lipid metabolic pathway was enriched, which may reduce abdominal fat accumulation in high-ryegrass fed geese.

Comparative Analysis of Intestine Microbiota of Four Wild Waterbird Species

Waterbirds are ubiquitous and globally distributed. Yet, studies on wild waterbirds' gut microbiota are still rare. Our aim was to explore and compare the gut microbial community composition of wild waterbird species. Four wild waterbird species that are either wintering or all-year residents in Israel were studied: great cormorants, little egrets, black-crowned night herons and black-headed gulls. For each bird, three intestinal sections were sampled; anterior, middle and posterior. No significant differences were found among the microbiota compositions in the three intestine sections of each individual bird. Each waterbird species had a unique microbial composition. The gut microbiota of the black-headed gulls' fundamentally deviated from that of the other bird species, probably due to a very high abundance (58.8%) of the genus Catellicoccus (Firmicutes). Our results suggest a correlation between the waterbird species' phylogeny and their intestine microbial community hierarchical tree, which evinced phylosymbiosis. This recent coinage stands for eco-evolutionary patterns between the host phylogeny and its microbiota composition. We conclude that eco-evolutionary processes termed phylosymbiosis may occur between wild waterbird species and their gut microbial community composition.

Gut Microbiota and Mucin Composition in Female Broiler Chickens Fed Diets including Yellow Mealworm (Tenebrio molitor, L.)

A total of 160 female broiler chickens were divided into four dietary treatments (control feed [C] and 5, 10 and 15% TM meal inclusion, respectively, with five replicate pens/treatment and eight birds/pen) to investigate the effects of Tenebrio molitor (TM) meal utilization on poultry gut microbiota and mucin composition. The cecal microbiota assessment displayed a shift in the beta diversity in chickens fed TM-based diets. The TM10 and TM15 birds showed a significant decrease in the relative abundance of Firmicutes phylum and lower Firmicutes:Bacteroidetes ratios (False Discovery Rate [FDR] < 0.05), respectively, than the TM5 group. The relative abundance of Clostridium, Alistipes and Sutterella genera significantly increased in TM chickens (FDR < 0.05), while birds fed TM-based diets displayed a significant decrease in the relative abundance of Ruminococcus genus in comparison with the C group (FDR < 0.05). Gut mucin composition evaluation revealed higher mucin staining intensity in the intestinal villi of TM5 birds than the other TM groups, as well as mucin reduction in the intestinal villi of TM10 birds when compared to the C group (p < 0.05). In conclusion, dietary TM meal utilization (especially the 10-15% inclusion levels) may negatively influence either the cecal microbiota or the intestinal mucin dynamics of broiler chickens.