Thymol in the intestinal tract of broiler chickens after sustained administration of thyme essential oil in feed

Plant compounds occurring in phytogenic feed additives are involved in different pharmacological activities in the animal organism. Since the digestive tract acts as a first line of defence against foreign compounds, it is necessary to outline its response to dietary supplementation with bioactive plant components. Little information is available on the bioactivity of thymol as the main bioactive compound of Thymus vulgaris L. essential oil (TEO). The main objective of the present study was to provide a detailed view of the concentrations of thymol in plasma and the content of individual intestinal segments (duodenum, jejunum, ileum, caecum and colon) of broiler chickens after 4 weeks of dietary supplementation with different TEO concentrations. 32 one‐day old Ross 308 hybrid broilers were randomly divided into four dietary treatment groups (0.00%, 0.01%, 0.05%, 0.1% w/w of TEO in the diet). Thymol concentrations in the duodenal chyme presented around 7% on average from the thymol amount administered in the feed. A significantly increased thymol amount was observed after 0.1% TEO addition to the diet compared with 0.01% TEO enrichment in the duodenal wall and gut content of jejunum, ileum, caecum and colon (p < 0.05). Thymol levels in the colon were significantly higher than in the ileum and about 1.7 times higher on average than those in the caecum. Significant coefficient of correlation was observed between thymol concentrations in plasma and feed, gut content of all intestinal segments as well as duodenal wall. Our results point to intensive thymol absorption in the initial sections of the digestive tract. In the current study, the role of intestine in biotransformation of thymol was observed, and it would be desirable to investigate whether thymol itself or thymol metabolites are responsible for beneficial effects in intestine.     

Chitosan nano-encapsulation improves the effects of mint,thyme, and cinnamon essential oils in broiler chickens

ABSTRACT

1. This study was conducted to evaluate the effects of chitosan nano-encapsulating mint (MEO), thyme (TEO) and cinnamon (CEO) essential oils (EOs) used in the diet on performance, immune responses and intestinal bacteria population in broiler chickens.

2. A total of 600 mixed-sex, 1-d-old Ross 308 broiler chicks were used in a 2 × 4 factorial experiment as completely randomised design with 8 experimental groups (diets) with 5 replicates of 15 chicks each (totally 40 pens). The eight experimental diets consisted of no EO and free distiller water (control); no EO and chitosan nano-encapsulated (CNE) distiller water; and other six treatments with free or CNE form of MEO, TEO and CEO (added at 0.025%, 0.04% and 0.055% respectively to starter, grower and finisher diets).

3. Both EOs and the CNE form had significant (P < 0.05) benefits on improving body weight gain, and feed conversion ratio in periods of 29–42 and 1–42 days. The highest effect was (P < 0.05) obtained in birds receiving TEO, which was intensified by nano-encapsulation. Breast percentage was improved by nano-encapsulation (P < 0.05). The EOs (especially TEO and CEO) and CNE form improved (P < 0.05) serum IgY and IgM concentrations (at 35 and 42 days) and intestinal Lactobacillus spp. and E. coli populations (at 42 days) in broilers. Nano-encapsulated EOs, especially TEO and CEO had (P < 0.05) the largest effect on increasing IgY₄₂ concentrations and the microbial populations.

4. The tested EOs, especially TEO, improved more of the evaluated traits in broiler chickens. Also, Chitosan nano-encapsulation because of its ideal properties can be an effective, suitable and inexpensive method for protecting bioactive compounds and improving effects of the herbal EOs especially thyme in broiler chickens.

     

Dietary taurine supplementation enhances antioxidative capacity and improves breast meat quality of broiler chickens

ABSTRACT

1. The aim of this study was to determine the effect of dietary taurine supplementation on growth performance, meat quality and antioxidant responses in breast muscle of broiler chickens.

2. A total of 72 Arbor Acres broiler chickens (28-day-old) with similar body weight were randomly allocated into two groups, and fed either 0 g/kg (control; C) or 5 g/kg taurine-supplemented diets (TS) for 14 days.

3. The results showed that TS had no effect on growth performance or chemical composition of breast muscle in broilers. The drip and cooking losses were significantly decreased (P < 0.05), and the pH_24h of breast muscle were increased (P < 0.05) in the TS group. Meanwhile, broilers in the TS group exhibited significantly higher (P < 0.05) scavenging activities of superoxide and 2,2-diphenyl-1-picrylhydrazyl radicals, and lower (P < 0.05) contents of carbonyl, malondialdehyde, and 4-hydroxynonenal. TS increased (P < 0.05) total antioxidant capacity and superoxide dismutase activities. Moreover, TS significantly upregulated (P < 0.05) the mRNA expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1, NAD(P)H quinone dehydrogenase 1, superoxide dismutase, catalase, and glutathione peroxidase.

4. These findings suggested that TS enhanced antioxidative capacity and improved breast meat quality of broilers via activating the Nrf2 pathway.     

Comparative analysis of differentially expressed genes related to triglyceride metabolism between intramuscular fat and abdominal fat in broilers

ABSTRACT

1. Lipid metabolism is an indispensable process in an organism, though little is known about the regulatory mechanisms of fat deposition in different types of adipose tissues.

2. The differentially expressed genes related to triglyceride (TG) metabolism between abdominal and intramuscular fat (IMF) of Beijing-You chickens were investigated in this study.

3. TG content in abdominal fat (AF) (349.7 mg/g) was significantly higher (P < 0.01) than in the breast and thigh (12.3 mg/g and 24.8 mg/g, respectively).

4. Using Agilent chicken gene-expression profiling in adipose tissues between AF and muscle (breast and thigh), certain representative genes related to fatty acid metabolism, lipoprotein catabolism and esterification reactions were significantly upregulated (P < 0.05 or P < 0.01).

5. Genes involved in fatty acid oxidation or carbohydrate utilisation were significantly up- or downregulated (P < 0.05 or P < 0.01), including those involved with highly enriched pathways of lipid metabolism (PPAR, Wnt pathway and inositol phosphate metabolism), cell junctions (focal adhesion and regulation of actin cytoskeleton) and muscle contraction.

6. Overall, higher TG levels were observed in AF tissue than in adipose tissues of breast and thigh, which could be regulated through gene expression of pathways related to lipid metabolism (PPAR, Wnt pathway and inositol phosphate metabolism), cell junctions (focal adhesion and regulation of actin cytoskeleton) and muscle contraction. These results provide clues to understanding the molecular mechanisms of TG metabolism between abdominal and IMF.     

Effects of carboxy methyl cellulose and thymol + carvacrol on performance,digesta viscosity and some blood metabolites of broilers

This study was conducted to evaluate the effects of thymol + carvacrol as plant essential oils on performance, digesta viscosity and some blood metabolites of broilers fed diets supplemented with carboxy methyl cellulose (CMC) and/or thymol+carvacrol. In a completely randomized design with a 2 × 3 factorial arrangement, two levels of CMC (0% and 2%) and three levels of thymol+carvacrol (0, 100 and 200 mg/kg) were used. Each of the six dietary treatments was fed to five replicate pens of 12 birds each from 0 to 42 days of age. Body weight gain (BWG), feed intake, feed conversion ratio (FCR), intestinal digesta viscosity and pH, plasma lipids and some blood metabolites were recorded. The inclusion of 2% CMC decreased (p < 0.05) BWG by 2.2% and increased FCR by 2.3% at 42 days of age. Carboxy methyl cellulose significantly increased the digesta viscosity and decreased serum total cholesterol, but had no significant effect on triglyceride, pH, HDL, LDL and other blood metabolites measured in this experiment. Thymol+carvacrol had no effect on feed intake, but significantly increased (p < 0.05) BWG from 1 to 42 days of age and improved FCR (p < 0.05) by the addition of 100 and 200 mg/kg thymol+carvacrol respectively. Inclusion of thymol+carvacrol at levels of 100 and 200 mg/kg in the diets decreased digesta viscosity and serum total cholesterol (p < 0.05) and also increased AST at a 200 mg/kg thymol+carvacrol without any effect on creatine kinase (CK). Thymol+carvacrol significantly increased total protein (TP), albumin and globulin (p < 0.05). In conclusion, CMC at an inclusion level of 2% of diet increased digesta viscosity and reduced growth performance. However, thymol+carvacrol decreased digesta viscosity and consequently improved the performance of broilers fed the CMC‐based diet. Therefore, thymol+carvacrol addition to viscose‐based diets might be helpful to alleviate the negative effects of viscous compounds in poultry diets.     

Feeding broilers with thyme essential oil loaded in chitosan nanoparticles: an efficient strategy for successful delivery

ABSTRACT

1. The use of chitosan nanoparticles (CNPs) for the entrapment of active components has gained considerable interest in food and pharmaceutical industries due to its mucous adhesiveness, non-toxicity, biocompatibility and biodegradability.

2. This study aimed to investigate the usefulness of feeding encapsulated thyme essential oil (E-TEO) on performance, blood parameters, immunity and ileal microflora in broilers.

3. CNPs were prepared by using ionotropic gelation and structurally characterised by dynamic light scattering; scanning electron microscope and Fourier transform infrared spectroscopy. The encapsulation efficiency percentage of TEO in CNPs and its in vitro release were determined using ultraviolet visible spectroscopy and dialysis method, respectively.

4. An in vivo experiment was conducted with five treatments of five replicates with ten chicks per pen. Dietary treatments consisted of an unsupplemented control diet, or supplemented with chlortetracycline (80 and 50 mg/kg during the starter and grower phase, respectively); CNPs (60 mg/kg); TEO (40 mg/kg diet) or E-TEO (60 mg/kg).

5. Results showed uniform distribution of nanoparticles with roughly spherical morphology, and the size of particles ranged from 30 to 100 nm. It was observed that 68.3% of TEO was encapsulated into CNPs, from which more than 90% was released within the first 96 h. Birds treated with antibiotic and E-TEO showed significantly (P < 0.05) higher body weight gain than the control and the other treatments were intermediate. Compared to the control group, adding of E-TEO into diet significantly (P < 0.05) improved feed conversion ratio at 42 days of age. Feeding birds with E-TEO significantly (P < 0.05) decreased the number of coliform and total aerobic bacteria compared to other treatments. Birds supplemented with E-TEO showed lower heterophile to lymphocyte ratio compared to birds that received TEO.

6. The results suggested that the entrapment of TEO in CNPs and its sustained release promoted broiler performance via the improvement of physiological status and modulating intestinal microbiota and therefore could be used as substitute for antibiotic growth promoter in broiler diets.     

Expression profiles and associations of FGF1 and FGF10 with intramuscular fat in Tibetan chicken

ABSTRACT

1. FGF1 and FGF10, two paracrine members of the fibroblast growth factor (FGF) gene family, play critical roles in the development, structural and metabolic remodelling of adipose tissue.

2. The objective of this study was to investigate the expression profiles of FGF1 and FGF10 genes in breast muscle and thigh muscle in 5 developmental stages (1, 81, 119, 154 and 210 d old) in Tibetan chickens. The possible relationships between expression of these genes and intramuscular fat (IMF) content were analysed in Tibetan chickens.

3. Expression profiles showed that FGF1 and FGF10 mRNA were ubiquitously expressed in various tissues of 154-d-old Tibetan chickens. Lung tissue contained the highest amount of FGF1 and FGF10 mRNA while breast muscle and thigh muscle exhibited lower levels of FGF1 and FGF10 mRNA in both males and females compared with other tissues (P < 0.05). Temporal expression of FGF1 and FGF10 in breast and thigh muscle showed similar tendencies in males and females, respectively, with peaks in thigh muscle at 119-d-old and breast muscle in 1-d-old males and females, respectively.

4. Correlation analysis suggested that gender had an influence on the relationships of FGF1 and FGF10 expression with IMF content in thigh muscle. The RNA levels of FGF1 and FGF10 genes in male thigh muscle were positively related to IMF content of Tibetan chickens (P < 0.01), while the correlations were shown to be negative in female thigh muscle (P > 0.05).

5. These results provide a basis for functional elucidation of FGF1 and FGF10 genes on adipocyte development and intramuscular fat deposition, as well as selective breeding and resource exploration of local poultry breeds.     

Effects of a selection of additives on in vitro ruminal methanogenesis and in situ and in vivo NDF digestibility

The effects of 18 essential oils, yeast, Quebracho tannin and Quillaja saponin on ruminal methane and gas production (GP) were studied in vitro. A lactating cow diet was incubated with rumen inoculum. Doses of the additives (mg/L) were: essential oils = 500; tannin = 67; yeast = 8.35 and 16.7; and saponin = 300. Lemongrass, estragole, eugenol, geraniol, limonen, thyme oil and thymol produced less gas (overall mean 33.8 mL/200 mg dry matter (DM)) than control (43.6 mL/200 mg DM; P < 0.001). Methane produced (mL/200 mg DM) by guaiacol (10.7), lemongrass (9.6), limonene (11.4), thyme oil (10.9) and thymol (2.1) was lower than control (12.5) (P < 0.001). Methane percentage on total GP was lower (P < 0.001) for cinnamic alcohol (25.4), guaiacol (24.5), thymol (19.7) and vanillin (26.3) than control (28.8). In a second experiment, thymol, guaiacol and yeast were added to the diet of dry fistulated cows to determine in situ neutral detergent fiber digestibility (NDFD) of six forages and in vivo dietary NDFD. Thymol and yeast decreased in situ NDFD after 24 h (33.9% and 33.5% vs. 38.1%; P = 0.008). Thymol decreased in vivo total tract NDFD (40.8% vs. 51.4%; P = 0.02). Differences in GP and methane levels were registered within classes of additives. A careful selection of additives may allow for the manipulation of ruminal fermentation.     

Production performance,immune response and blood biochemical parameters in broiler chickens fed diet incorporated with prebiotics

This experiment was conducted to identify the suitable replacer of broiler feed antibiotics with prebiotics (mannan oligosaccharides‐MOS or fructooligosaccharide‐FOS). Two hundred and forty (240)‐day‐old chicks were randomly divided into 30 groups (6 treatments x 5 replicates/treatment x 8 chicks/replicate). Six experimental diets T₁, T₂, T₃, T₄, T₅ and T₆ were formulated to contain an additional 0, antibiotic, that is, bacitracin methylene di‐salicylate (BMD) @20 mg/kg, MOS (0.1% and 0.2%) and FOS (0.1% and 0.2%) respectively. Body weight gain was significantly (p < 0.05) increased in MOS‐0.2% supplemented group at 0–21 d and 0–42 d of broiler chicken. Humoral and in vivo cell‐mediated immune response were significantly improved (p < 0.05) in BMD, MOS @0.1% or 0.2% treated group. Significant (p < 0.05) increase was recorded in total protein (except 21 d), albumin and aspartate amino transferase (AST) and decrease (p < 0.05) in alanine amino transferase (except 42 d), cholesterol and uric acid concentration. The weight of breast, thigh, back, drumstick bursa of Fabricius and thymus were higher (p < 0.05) in the birds given the MOS @0.2% (T₄). It is concluded that MOS @0.2% may be suitable replacer of antibiotic growth promoter, and it has a beneficial effect on production performance, immune responses, blood biochemical parameters and cut up parts in broiler chickens.     

Effects of thermo‐resistant non‐starch polysaccharide degrading multi‐enzyme on growth performance,meat quality,relative weights of body organs and blood profile in broiler chickens

This research was conducted to study the performance and carcass parameters of broiler chickens fed diets supplemented with heat‐treated non‐starch polysaccharide degrading enzyme. A total of 432 one‐day old Ross 308 broiler chickens were allocated to five treatments: (i) CON (basal diet), (ii) E1: CON + 0.05% multi‐enzyme, (iii) E2: CON + 0.1% multi‐enzyme, (iv) E3: CON + 0.05% thermo‐resistant multi‐enzyme and (v) E4: CON + 0.1% thermo‐resistant multi‐enzyme, each treatment consisted of six replications and 12 chickens in each replication. The chickens were housed in three floor battery cages during 28‐day experimental period. On days 1–7, gain in body weight (BWG) improved by feeding the diets supplemented with thermo‐resistant multi‐enzyme. On days 7–21 and 1–28, chickens fed the diets containing thermo‐resistant multi‐enzyme showed improved (p < 0.05) BWG and feed conversion ratio (FCR) compared to CON group. Supplementing the diets with multi‐enzyme or thermo‐resistant multi‐enzyme affected the percentage of drip loss on d 1 (p < 0.05). Drip loss percentage on days 3 and 5 and also meat colour were not affected significantly. Supplementing the diets with multi‐enzyme or thermo‐resistant multi‐enzyme did not affect the relative weights of organs but compared to CON group, relative weight of breast muscle increased and abdominal fat decreased (p < 0.05). Among measured blood constituents, chickens fed supplemented diets with thermo‐resistant multi‐enzyme showed higher (p < 0.05) IgG. Counts of red and white blood cells and lymphocyte percentage were not affected. In conclusion, the results demonstrated that supplementing pelleted diets with thermo‐resistant multi‐enzyme improved performance of broiler chickens.     

Enterococcus faecium NCIMB 10415 supplementation improves the meat quality and antioxidant capacity of muscle of broilers

The present study was conducted to investigate the effects of Enterococcus faecium (E. faecium) on the meat quality and antioxidant capacity of muscle in broilers. A total of 600 Arbor Acre broiler chickens (1‐day‐old, male) were randomly divided into five treatments with six replicates (20 chickens per replicate) for each treatment. The five treatments were the control treatment (CON, basal diet), antibiotic treatment (ANT, basal diet supplemented with 0.1% chlortetracycline) and E. faecium‐supplemented treatments (LEF, MEF and HEF, basal diet supplemented with 50, 100 and 200 mg/kg of E. faecium respectively). The experiment lasted 42 days in two periods of 21 days. Results showed that there were no differences in breast meat quality among different treatments (p > 0.05). Compared with the CON and ANT treatments, the yellowness of thigh meat in E. faecium‐supplemented treatments was significantly increased (p < 0.05); the shear force of thigh meat in the LEF and MEF treatments was lower than that of the CON treatment (p < 0.05). In addition, the concentration of the inosine monophosphate (IMP) in the breast and thigh meat of the MEF treatment was significantly higher than that of the other treatments (p < 0.05). At 21 days, the total antioxidant capability (T‐AOC) level and glutathione peroxidase (GSH‐Px) activity of breast meat and superoxide dismutase (SOD) in the thigh meat of the MEF treatment were greatly increased (p < 0.05). At 42 days of age, the catalase (CAT), GSH‐Px and T‐AOC activities in the breast meat of the MEF treatment were increased (p < 0.05) and the CAT activity of thigh meat in the LEF and MEF treatments was increased (p < 0.05). In conclusion, E. faecium supplementation increased the meat quality of the thigh muscle, increased the IMP content and the activities of CAT, SOD, T‐AOC, and GSH‐Px of muscle in broilers. Supplementation with 100 mg/kg E. faecium had the greatest effects.     

Growth performance and carcass characteristics of broiler chickens fed diets supplemented with graded levels of charcoal from maize cob or seed of <Emphasis Type="Italic">Canarium schweinfurthii</Emphasis> Engl

Growth performances and carcass characteristics of broiler chickens fed diets supplemented with graded levels of Canarium schweinfurthii Engl seed (charcoal A) or maize cob (charcoal B) were studied using a total of 110 3-week-old male chicks. 11 experimental diets including a control and other containing either 0.2, 0.4, 0.6, 0.8 or 1% charcoal from C. schweinfurthii Engl seed (A_0.2, A_0.4, A_0.6, A_0.8, and A_1%, respectively) or from maize cob (B_0.2, B_0.4, B_0.6, B_0.8, and B_1%, respectively) supplements were used. Each of the diets was fed to ten individually birds caged in a completely randomized design. Results indicated that birds fed 0.2, 0.4, and 0.6% of either charcoal A or B had significantly (P < 0.05) higher final body weights as compared to control birds, while, above 0.6% slightly depressed average final body weights and weight gain. The best growth performance was achieved with 0.2% inclusion of charcoals. There was no significant (P > 0.05) influence of charcoal B on the overall feed intake. Only the B_0.6 feed significantly (P < 0.05) improved feed conversion ratio as compared with the control. Dressing percentage, liver weight and abdominal fat were not significantly (P > 0.05) affected by charcoal. However, there was a significant (P < 0.05) reduction in gizzard weight with charcoal B. Charcoal had no significant (P > 0.05) influence on intestine length and weight. More than 0.6% of charcoal A significantly (P < 0.05) depressed intestine density. It was concluded that under the conditions of this study, charcoal from maize cob or Canarium seeds could be used to improve growth performances and some carcass traits in broiler chickens.     

Dietary supplementation with acidifiers improves the growth performance,meat quality and intestinal health of broiler chickens

This experiment was conducted to study the effects of dietary supplementation with acidifiers on the growth performance, meat quality, and intestinal health of broiler chickens. A total of 648 male Arbor Acres broiler chickens at 1 d old were randomly divided into 6 groups, and each group consisted of 6 replicates with 18 broilers per replicate. The dietary treatments were as follows: negative control (NC, the basal diet), NC + antibiotic (enramycin, 8 mg/kg, positive control [PC]), NC + phosphoric acid (PA, 0.1, 0.2, and 0.3 g/kg), and NC + lactic acid (LA, 0.3 g/kg). The feeding trial lasted for 42 d. The results showed that the feed-to-gain ratio of the NC + acidifier groups was lower than that of the NC and PC groups from 1 to 42 d (P < 0.05). Compared with the values in the NC group, the pH of breast muscle was significantly higher in the NC + PA (0.2 g/kg) and LA (0.3 g/kg) groups (P < 0.05), and the cooking loss was lower in the breast muscle of the NC + PA (0.1 g/kg) and LA (0.3 g/kg) groups (P < 0.05). In addition, the shear force of the breast muscle and thigh muscle and the pH value in the crop, gizzard and duodenum of the antibiotic and acidifier groups were significantly decreased (P < 0.05). Moreover, the trypsin, chymotrypsin, and lipase activities of the duodenum in the NC + PA (0.2 and 0.3 g/kg) groups, as well as the villus height-to-crypt depth (VH:CD) ratio of the duodenum in the NC + PA (0.1 g/kg) group was significantly greater (P < 0.05) compared with those in the NC group. Meanwhile, the number of total aerobic bacteria, Escherichia coli and Salmonella in the cecum of the NC + PA (0.1 g/kg) and LA (0.3 g/kg) groups were decreased (P < 0.05). Collectively, diet supplementation with acidifiers could improve the growth performance, meat quality, and intestinal health of broilers, in which the effects of PA (0.1 g/kg and 0.2 g/kg) are better than the other supplementations.     

Effects of different rearing systems on meat production traits and meat fiber microstructure of Beijing‐you chicken

Beijing‐you is a Chinese local chicken which is raised for both meat and eggs. In the present study, we detected the effects of different rearing systems on growth, slaughtering performances and meat quality of Beijing‐you chickens at 26–40 weeks of age. Six hundred Beijing‐you hens were randomly allocated into two groups at 16 weeks of age and raised in free range or battery cage systems. The body weight, slaughtering performance and meat quality were measured for each group at the ages of 26, 30, 35 and 40 weeks. Some of the traits were dramatically influenced by the two systems, although most of them did not show significant changes. For the meat fiber microstructure, we found that the diameter of thigh and breast muscle fiber in the free range group were significantly increased than in the cage group (P < 0.05) at 26 weeks of age. The ratio of fast muscle fiber in thigh muscle samples of the free range group was significantly reduced compared to that of cage group at both 35 (P < 0.01) and 40 (P < 0.01) weeks of age, indicating that the free range system could promote the transforming of fast muscle fiber to slow muscle fiber.     

Effects of probiotic lactic acid bacteria on growth performance,carcass characteristics,hematological indices,humoral immunity,and IGF-I gene expression in broiler chicken

The effects of screened lactic acid bacteria strains were evaluated on growth performance, humoral immunity, and IGF-1 gene expression in broiler chickens. The three dietary groups of negative control fed basal diet, the native LAB probiotic group (NP), and PrimaLac commercial LAB probiotic (PC) were studied. The results revealed that NP and PC diets significantly improved feed conversion ratio and increased body weight, as well as relative weight of carcass compared with group fed NC diet (P?<?0.05). Lymphocyte level was significantly increased in birds fed NP and PC (P?<?0.01), while serum triglycerides and total cholesterol levels were significantly decreased compared with the NC (P?<?0.05). Significant increases were observed in antibody titers against Newcastle disease virus of vaccinated birds (P?<?0.03), and morphological analysis of ileum revealed significant increases (P?<?0.05) in the villus height and villus height/crypt depth in birds fed NP and PC compared with the NC. The dietary significantly increased Lactobacillus spp. (P?<?0.05), while Escherichia coli (P?<?0.04) populations were significantly decreased, and also, the expression of IGF-1 gene in liver tissue of broilers fed NP and PC was significantly increased compared with the NC (P?<?0.05). These results indicated that the identified native LAB strains can be used commercially as a low-cost probiotic in poultry industry of Iran.

     

Effect of dietary fermented fish waste on the digestion of feed and supply of unsaturated fatty acids including conjugated linoleic acid in cattles

Abstract

This study was conducted to evaluate the effect of fermented fish waste (FW) on the digestion of fiber and the flow of unsaturated fatty acids (UFA) to the duodenum and plasma in cattle. Four Holstein cows were used in a 4×4 Latin square design and cows were provided with one of four treatments consisting 0, 5.5, 11, and 16.5% of FW. The digestion of dry matter decreased as the FW increased; however, the lipid concentration increased linearly (P<0.05) as the FW increased. According to the duodenal composition, the lipid concentration and UFA such as conjugated linoleic acid (CLA), arachidonic acid, and docosahexaenoic acid (DHA) increased linearly (P<0.05) as the amount of FW increased in the diet. Additionally, the concentration of CLA, eicosapentaenoic acid and DHA increased linearly (P<0.05) in the plasma as the FW increased. Thus, these findings indicate that FW can be useful as UFA supplementation of feedstuff.     

Gender,caponization and exogenous estrogen effects on lipids,bone and blood characteristics in Taiwan country chickens

This study investigated gender, caponization and exogenous estrogen effects on lipids, bone and blood characteristics in Taiwan country chickens. Thirty male chickens were caponized at 8 weeks (capons); 15 capons were injected with estrogen (5 mg/bird estradiol 3‐benzoate) every 2 weeks from 8 to 28 weeks, and 15 sham‐operated male (shams) chickens and 15 females were selected for this trial. The results showed that the shams had lower relative abdominal and chest subcutaneous fat than females (P < 0.05). The estrogen‐treated capons had greater relative abdominal and chest subcutaneous fat than shams and capons (P < 0.05), which might result from higher blood very low‐density lipoproteins and triacylglycerol concentrations (P < 0.05). Caponization could dramatically increase relative abdominal fat (506%; P < 0.05). The shams had higher tibia weight and biomechanical properties, such as maximum bone strength and bending moment values than the capons (P < 0.05). Tibia biomechanical properties were reduced by estrogen treatment (P < 0.05). The females obtained the lowest biomechanical value in all treatments (P < 0.05). Histological examination revealed cavity formation in the cortical bone of estrogen‐treated capons and female chickens, which suggested that estrogen reduced bone biomechanical properties by destroying its structural integrity.     

Effects of nutritional level of concentrate‐based diets on meat quality and expression levels of genes related to meat quality in Hainan black goats

The present study investigated the effects of the nutritional levels of diets on meat quality and related gene expression in Hainan black goat. Twenty‐four goats were divided into six dietary treatments and were fed a concentrate‐based diet with two levels of crude protein (CP) (15% or 17%) and three levels of digestive energy (DE) (11.72, 12.55 or 13.39 MJ/kg DM) for 90 days. Goats fed the concentrate‐based diet with 17% CP had significantly (P < 0.05) higher average daily gains (ADG) and better feed conversion rates (FCR). The pH _24h value tended to decrease (P < 0.05) with increasing DE levels. The tenderness of Longissimus dorsi muscle (LD) and Semimembranosus muscle (SM) reduced with increasing CP levels (P < 0.05). With increasing DE levels, tenderness was increased (P < 0.05). The heart fatty acid‐binding protein (H‐FABP) mRNA expression levels in LD and SM increased with increasing DE levels (P < 0.05), but decreased with increasing CP levels (P < 0.05). The calpastatin (CAST) and μ‐calpain mRNA expressions levels in LD and SM were affected significantly (P < 0.05) by CP and DE levels in the diet. Therefore, the nutritional levels of diets affect meat quality and expression levels of genes associated with meat quality in Hainan black goats.     

Dietary thymol supplementation promotes skeletal muscle fibre type switch in longissimus dorsi of finishing pigs

As one of the key points related to meat quality, skeletal muscle fibre type is determined by energy metabolism and genetic factors, but its transformation could be also greatly influenced by many factors. Thymol, the primary effective ingredients of thyme, is well known for its anti-oxidation and anti-inflammatory, while little is known about its effect on skeletal muscle oxidative metabolism and fibre type switch. Therefore, in order to investigate its effects and possibility to be applied in livestock production, 36 150-day-old fattening Pigs were fed with different diet for six-week experiment. As a result, the drip loss ratio of longissimus dorsi (LD) was significantly reduced (p < .05). Oxidative metabolism-related enzyme activity, the mRNA levels and protein expression of COX5B and PGC1α, mRNA level of myosin heavy chain I (MyHC I) and protein level of MyHC IIa were significantly upregulated (p < .05). While compared with control group, the protein expression of MyHC IIb was significantly decreased (p < .05). The result revealed that thymol could promote the oxidative metabolism in the muscle of pigs and improve the meat quality to a certain extent.     

Evaluation of bee venom as a novel feed additive in fast-growing broilers

1. The present study was designed to evaluate purified bee venom (BV) as an alternative to antibiotics in broiler chickens. The experimental treatment diets were formulated by adding BV into a maize-soybean meal-based diet to give 0, 10, 50, 100, and 500 μg BV per kg of diet.

2. Dietary BV quadratically improved (P < 0.05) feed conversion ratio and increased body weight gain at 1–21 d as level in diet increased. Higher BV levels lowered relative weight of spleen (linear and quadratic, P < 0.05), bursa of Fabricius (quadratic, P < 0.05), and liver (linear and quadratic, P < 0.05) at 21 d of age. Relative breast meat yields were increased quadratically at 21 d and linearly at 35 d with supplementation levels. Dietary BV increased (linear and quadratic, P < 0.05) lightness (L*) value for meat at 21 d, decreased (linear, P < 0.05) ileal villus height and narrowed (quadratic, P < 0.05) width.

3. Dietary BV inclusion linearly increased the concentration of secretory immunoglobulin A (sIgA) on ileal mucosa at 21 d and decreased (quadratic, P < 0.05) nitric oxide contents in serum samples at 21 d and 35 d. Total short-chain fatty acids (SCFA) in caecal digesta were reduced with increasing venom in diets at 21 d of age. None of the serum parameters except for creatinine was affected by dietary BV.

4. It was concluded that dietary BV exhibited wide range of in vivo biological properties in broiler chickens and could be incorporated into feed to promote growth and animal health.