Abstract in English:ABSTRACT This study was conducted to compare edible giblets weight, tibial bone mineral density (BMD), and bone mineral content (BMC) of two slow-growing broiler genotypes (Hubbard S757; S757 and Hubbard Grey Barred JA; GB-JA) reared with outdoor access, and to determine the relationship between these variables. Day-old chicks (straight-run) of the genotypes S757 (n=120) and GB-JA (n=120) were housed for 98 days. Each genotype was assigned to six pens of 20 birds each. Birds were reared in indoor floor pens and moving shelters with outdoor access (during daylight hours). Absolute body (BW), heart (HW), spleen (SW), liver (LW), gizzard (GW), and abdominal fat pad (AFW) weights of the genotype S757 and male birds were statistically higher than that of the genotype GB-JA and female birds. Genotype statistically affected relative HW, whereas sex affected relative GW. Although BMD values were not influenced by genotype or sex, S757 birds and males presented statistically higher tibial BMC, lean, lean+BMC, total mass values (g) and area (cm2) compared with GB-JA birds and females. BW, HW, SW, LW, GW and AFW were positively correlated with BMC obtained by DXA. In conclusion, the measured traits influenced by genetic strain and sex. The use of the Hubbard S757 genotype in organic production systems with outdoor access is recommend.
Abstract in English:ABSTRACT Heat tolerance in poultry production was obtained attention due to the need for genetic lines that can withstand climate changes. This study aimed at investigating heat tolerance in commercial and native broiler genetics, as well as the physiological and growth performance responses of HSP70 genotypes submitted to heat stress. In Experiment I, heterophil:lymphocyte (H:L) ratio, as an indicator of heat tolerance, was compared between commercial broilers (n = 100) and Thai native chickens (n = 100). Growing chickens (with similar initial weight) of each genetic strain were randomly divided into two groups: 1) thermoneutral environment (26 oC ± 2 oC) and 2) heat stress (36 oC ± 2 oC). The results showed that native chickens originating from a tropical environment presented lower H:L ratio and mortality rate compared with commercial broilers. In Experiment II, HSP70 genotypes were compared. PCR-RFLP was applied to identify the genotypes (C1C1, n = 38; C1C2, n = 38; and C2C2, n = 28). Ten-week-old chickens of each genotype were evaluated in the same environments described in Experiment I. Heat-stress indicators - respiratory rate (RR), cloacal temperature (CT), packed cell volume (PCV), and average daily gain (ADG) - were measured for three weeks. The significant difference in PCV indicated that C2C2 chickens were less tolerant to heat stress compared to other genotypes. The RR, CT, and ADG were not significantly different among all genotypes. Since the C2C2 genotype was shown to be sensitive to heat stress, C1C1 and C1C2 could be used as markers for heat-tolerant genetic strains of Thai indigenous chickens and hybrid commercial lines.
Abstract in English:ABSTRACT The present study evaluated a probiotic and a competitive exclusion product injected in ovo on day 18 of incubation together with Marek's disease vaccine in eggs of 56-week-old broiler breeders. Three experiments were carried out. The first trial evaluated the effect of treatments on hatchability, cecal colonization of Salmonella Heidelberg (SH), and intestinal mucosa immunity (immunoglobulin A levels in the intestinal fluid). The second trial evaluated the viability of the microorganisms in the products inoculated in a solution containing diluent and Marek's disease vaccine. The third trial evaluated the colonization of the cecal microbiota in non-challenged chickens during first four days of life by culturing cecal samples under aerobic and anaerobic conditions. Hatchability was not affected by the treatments. SH cecal counts were reduced in three-day-old broilers inoculated in ovo with the competitive exclusion product. Liver and spleen pool SH counts were not different among treatments. Broilers inoculated in ovo presented higher intestinal IgA titers 24 hours after SH challenge compared with the controls. When birds were not challenged, lower cecal microbial counts in aerobic culture were determined in the control group than in the probiotic group on day 3, and in the competitive exclusion group on day 2 when cultured in anaerobiosis. The products inoculated and diluted in the vaccine solution were viable at all analyzed periods when cultured in anaerobiosis. The results of this study suggest in-ovo inoculation is an effective route for the administration of the evaluated products, which effectively enhanced the broilers' immune response to a SH challenge, as shown by the increase in IgA titers, and the reduction in cecal Salmonella Heidelberg colonization with the in-ovo inoculation with the competitive exclusion product.
Abstract in English:ABSTRACT The objective of this study was to select the best non-linear model that fits the growth curve of turkeys managed under the tropical conditions of Southern Mexico. Data from 481 Hybrid converter turkeys (236 females and 245 males) reared under commercial conditions typical of that region were used. Turkeys were given ad libitum access to feed and water. Body weight was weekly recorded from 1 day to 23 weeks of age. Five non-linear mathematical models (Brody, Gompertz, Logistic, von Bertalanffy and Richards) were chosen to describe the age-weight relationship. The Brody and Richards' models fail to converge. The best fitting model was chosen based on the average prediction error (APE); the multiple determination coefficient R2 and the Akaike information criterion (AIC). In both sexes, von Bertalanffy and Gompertz were the best models. The highest estimates of parameter A (mature weight) for both females and males were obtained with the von Bertalanffy model followed by the Gompertz and Logistic. The estimates of A were higher for males than for females. The highest estimates of parameter k (rate of maturity) for both females and males were, in decreasing order for the Logistic, Gompertz, and von Bertalanffy models. k values for female turkeys was higher than for males. The age at the point of inflection and body weight at the age of point of inflection varied with the model used. The largest values of TI and WI corresponded to the Logistic model. Between sexes, the largest TI and WI values corresponded to males. The best models to describe turkey growth were the von Bertalanffy and Gompertz models, because it presented the highest APE, R2 and AIC values.
Abstract in English:ABSTRACT In total, 806 eggs of free-range Hassawi indigenous chickens were collected from local farm in Saudi Arabia. Eggs were weekly collected for 11 weeks. Initial egg weight (IEW) was recorded, and eggs were graded into four classes (A: 35-40 g, B: 40-45 g, C: 45-50 g, and D: 50-55 g). Eggs were stored for seven days at 75-80% relative humidity and 14-16 C, after which egg weight losses (WL0) were calculated. During incubation, eggs were weighed on days 7 (W7) and 14 (W14), and egg weight losses on days 7 (WL7) and 14 (WL14), and total loss (WL0-14) were calculated. Hatchling weight (CW) was measured. The proportion of CW relative to egg weight loss (WL) on days0, 7 and 14 days of incubation (CW:WL0; CW:WL7 and CW:WL14, respectively), and break out analyses, fertility (F),total hatchability (HC) and hatchability of fertile eggs (HF) were also calculated. IEW decreased (p<0.05) with hen age. Stored egg weight (SEW) were decreased as hen age increased (p<0.05). WL7, WL14 and WL0-14 showed significant differences (p<0.001) and increased up to first six-week of egg collection time. Hen age affected CW:WL before incubation, and on days 7 and 14 of incubation. Fertility (F) was affected (p<0.05) in unpredicted way of increasing and decreasing by hen age. Egg weight class affected SEW, W7and W14 (p<0.001). Class D eggs were the highest weight. Class C eggs had highest HC. In summary, hatching eggs of Hassawi hens were affected by hen age and egg weight in randomly increase and decrease .
Abstract in English:ABSTRACT The objective of the study was to investigate the influence of anise seed (Pimpinella anisum L.) powder supplemented to the drinking water on selected blood parameters of broilers. In total, 360 one-day-old Hubbard Classic chicks were randomly divided into four groups with three replicates of 30 birds each. Anise seed powder was added at 0, 500, 750, and 1000mg/L to the drinking water offered to the C (control), T1, T2, and T3 groups respectively. The supplement was supplied for 56 days. When broilers were 28 and 56 days old, blood samples were collected (30 birds per group) by brachial vein puncture to evaluate the cellular components of blood (RBC, WBC, Hgb, HCT, H/L). The following serum biochemical parameters were evaluated: CHOL, GLU, TP, albumin, globulins, Ca, P, TG, total lipids, UA, and creatinine, as well as AST and ALT enzyme activities. The statistical analysis indicated that the anise supplement significantly improved blood RBC, WBC, Hgb, HCT, TP, albumin, globulin, GLU, P, and Ca levels of broilers in groups T4, T3, and T2 compared with the control group on days 28 and 56, and on average. Also, T3, T2 and T1 presented lower H/L ratio and CHOL, TG, total lipids, creatinine, UA, AST and ALT serum levels compared with the control group. The highest inclusion levels of anise seed powder, i.e., 1000 and 750mg/L, had a stimulating effect on the physiological traits of the birds.
Abstract in English:ABSTRACT The aim of the study was to determine body weight and dimensions, body conformation, length of the esophagus, length of intestine and its segments, as well as weight of internal organs and their proportions relative the body weight of broiler chickens from three commercial lines - Ross 308, Hubbard Flex and Hubbard F15. At the age of 42 days, Ross 308 chickens had significantly (p≤0.05) shorter trunk, but greater chest circumference and compactness index, as well as shorter esophagus and longer large intestine compared with Hubbard F15. The longest large and total intestine was found in Ross 308 broilers. Chicken genotype had no significant effect on the percentage of the main internal organs, i.e. liver, heart, proventriculus, gizzard, and spleen. In the analyzed broilers, the coefficients of correlation between body weight and dimensions and the length of the esophagus, small intestine, caeca and large intestine were low and not significant. This study provides information relevant to breeding practice, including that the development of internal organs in broiler chickens raised under intensive conditions has an effect on their meat characteristics.
Abstract in English:ABSTRACT Animal lysozymes, which have been studied in many of invertebrate and vertebrate species, have been characterized and demonstrated to be immune-associated molecules, digestive enzymes and multifunctional molecules. The purpose of this study was to detect the connection between lysozyme-gene polymorphism and the production traits of a Chinese native chicken breed (Langshan chicken). Four single nucleotide mutation sites were identified: G345A, C1726T, G1836A, A1838G. By the linkage disequilibrium analysis, six haplotypes and 15haplotype combinations were depicted in the studied population. The statistical analysis demonstrated that the SNPs and the haplotype combinations are related to body weight at sixteen weeks of age in Langshan chickens (p<0.05), and those with combined haplotype Hap3-Hap6 (GA-TT-GG-AA) presented higher body weight. Our study demonstrated that the SNPs and their haplotype combinations in the lysozyme gene were associated with the chicken production traits, and that SNPs can be used as a molecular marker for chicken marker-assisted selection.
Abstract in English:ABSTRACT The objectives of this study were to evaluate the effect of marination on marinade uptake of chicken carcasses and to determine the meat quality of carcass parts. In total, 45 eviscerated chicken carcasses were divided into three marinating treatments: no marination, marination in water, marination in non-phosphate and low-salt solution (NPLS). The study showed that the marinade uptake of chicken carcasses was higher than 4.0% for NPLS marination and than 3.5% for water marination when compared with the non-marinated treatment. However, raw chicken meat yield after cut-up was not significantly different (p≥0.05) among treatments. Carcasses marinated in NPLS solution presented higher water-holding capacity (WHC). The results showed that NPLS marination may reduce cooking loss and expressible water of chicken meat after cooking. Based on the Warner-Bratzler Shear (WBSF) results, NPLS marination had a stronger effect on textural quality of cooked breast meat than thighs and drumsticks. However, no significant differences of texture profile analysis (TPA) parameters were observed (p≥0.05). In the sensory evaluation, NPLS marination influenced the sensory quality of cooked meat, particularly texture and appearance attributes, but not the taste and aftertaste attributes of cooked meat. It is concluded that NPLS marination effectively increased carcass weight, despite its effects on meat quality varied according to the anatomical location of the parts.
Abstract in English:ABSTRACT There are several causes of carcass condemnation in poultry processing plants, including dorsal cranial myopathy (DCM), in which the anterior latissimus dorsi (ALD) muscle is affected. DCM etiology has not been elucidated yet, but this lesion impairs the visual quality of carcasses and causes economic losses due to downgrading and condemnation. The effects of this lesion on the systemic health of broilers are still unknown. In this context, the objective of this study was to evaluate muscle injury and systemic health indicators in broilers presenting or not DCM. The following parameters were evaluated: complete blood count (CBC), total protein, albumin, globulin, cholesterol, lactate, and glucose serum levels, aspartate aminotransferase (AST) and creatine kinase (CK) serum activities, and breast muscle pH. Blood samples were collected from 800 42-day-old broilers before feed withdrawal and transportation. In the processing plant, 28 carcasses presented DCM during inspection, and 28 carcasses with no DCM were used as controls. Blood biochemical parameters were not significantly different between broilers with DCM and the controls, except for AST and CK, which activities were higher in the DCM group than in the control group, suggesting that the DCM does not affect the systemic health of the broilers.
Abstract in English:ABSTRACT Brazil plays an important role in global poultry production as it is the world's largest chicken exporter and the third largest broiler producer. Despite the development achieved by the Brazilian broiler industry as a result of the integrated production system, many obstacles still need to be overcome, in particular, housing environment. In this regard, detailed knowledge of the inputs, outputs, and primary waste generated by broiler production cycles is essential to establish a baseline for energy balance research studies and to develop environmental solutions. This article proposes a mass balance of conventional broiler houses of southern Brazil sheds in order to predict their outputs, but that may also be applicable to other regions with similar climate. Control volumes considered the heating, cooling, and rearing processes. All generated products and wastes were estimated considering litter production and the total production per cycle. Despite the variety of the microclimates, the results were very close to those reported in experiments, indicating that this model is adequate for this kind of estimation.
Abstract in English:ABSTRACT Toll-like receptors (TLRs) are well-characterized in mice and rats, but little is known on their role in broiler chickens during acute heat stress (AHS). The aim of the present study was to estimate the change in TLR4 mRNA expression in the liver, kidney's pleen, heart, and small intestine of broiler chickens under AHS. A total of 240 healthy Arbor Acres (AA) broiler chickens were randomly divided into four groups: control group (22±1°C; 0h), HS2, HS5 and HS10 (38±1°C; 2h, 5h and 10h of heat stress, respectively). As AHS duration increased, TLR4 mRNA expression slightly decreased at HS2 and HS5, but was dramatically elevated in HS10 (p<0.001) compared with the control group in the small intestine, as well as in the spleen at HS2 (p=0.001) and HS10 (p<0.001). The mRNA expression levels of TLR4 significantly increased in the liver, heart, and kidneys (p<0.001) at HS10, and in the kidneys at HS5 (p=0.003). It is found that TLR4 mRNA expression at HS10 in different organs was significantly higher (p<0.001) compared with HS2 and HS5. The results of the present study suggest that AHS may modulate the functional responses of the liver, kidney, spleen, heart, and small intestine of broilers by regulating TLR4 mRNA expression.
Abstract in English:ABSTRACT Poultry farms in Central Argentina are often infested by Mus musculus L., despite the regular application of the rodenticide bromadiolone. This failure may be explained by the consumption pattern of mice, which may prefer alternative foods available on the farms to bromadiolone baits. Here we examine the consumption pattern of bromadiolone in the presence of wheat by M. musculus infesting poultry farms compared with the laboratory CF1 mouse strain. Overall, the poultry farm mice had longer survival and lower total food consumption in comparison with the CF1 mice. On the first day of the experiment, rodents from both strains and sexes consumed bromadiolone in the same proportion as wheat. On the second day, female mice of both origins showed a significant decrease in the consumption of bromadiolone, while males kept that proportion constant. Despite the consumption differences between males and females, survival rates were not different. We concluded that rodents from farms behaved as if they had never been in contact with bromadiolone, since they showed the same pattern of poison consumption that the CF1 mice. Females may have associated physical upset with the consumption of bromadiolone, since they decreased its consumption relative to wheat. However, this consumption pattern did not help them to achieve higher survival than males. On poultry farms, the balanced food fed to chickens may function as an alternative food to the poison for rodents. Therefore, we propose that rodenticide should be applied during downtime, when shed are cleaned and there is no chicken feed, which could be used as alternative food.
Abstract in English:ABSTRACT The objectives of this study were to evaluate the antimicrobial resistance and the biofilm-producing ability of Salmonella sp. strains isolated from frozen poultry carcasses. Antimicrobial susceptibility was tested by the disk-diffusion method. Biofilm-producing ability was determined in 96-well polystyrene microplates stained with crystal violet at 1%. Out of the 22 strains tested, all were multiresistant, that is, resistant to more than three antimicrobial classes, and 72.7% were able to form biofilms. The highest resistance rates obtained were against sulfonamides, tetracycline, and quinolones. On the other hand, 100% of the strains were sensitive to chloramphenicol. According to the rate of biofilm formation, 3 (13.6%) and 13 (59.1%) strains were classified as moderate and weak biofilm-producers, respectively, and 27.3% did not form biofilms. Biofilms increase the tolerance of microorganisms to stress, reducing their sensitivity to disinfectants and antimicrobials; favor equipment corrosion; and act as substrates for the adhesion of bacteria with lower biofilm-producing capacity. The results of the present study stress the importance of cleaning procedures in food processing plants and highlight the public health risks related to the emergence of multiresistant strains.
Abstract in English:ABSTRACT Griller-type chickens are broilers slaughtered between27and 29 days old weighing 1.3 to 1.5 kg and sold as a whole carcasses. The aim of the present study was to evaluate the growth performance, carcass traits, and meat quality of female broilers of four genetic lines reared for the production of griller-type chickens. A total of 960 broiler chicks was allotted in a randomized block design with four treatments and eight replicates of 30 birds per experimental plot. Each experimental treatment consisted of four different commercial lines, identified as A, B, C and D. The analyzed parameters were weight gain, feed intake, feed conversion ratio, livability, production efficiency index, carcass and cut yields, and meat quality according to breast meat color (L*, a*, b*), water-holding capacity (WHC), cooking losses, and shear force. Weight gain, feed intake, feed conversion ratio, and livability were different (p<0.05) among the lines; however, no differences were observed for the production efficiency index. Results show that lines presented similar performance; however, lines A, B, and C had a better carcass and breast yield, and line A, the best meat quality. Therefore, line A would be the most suitable for the production of griller-type chickens.
Abstract in English:ABSTRACT This experiment was conducted to investigate the effects of Bacillus coagulans on the growth performance and immune functions of the intestinal mucosa of yellow broilers. Three hundred and sixty one-day-old yellow chicks were randomly allocated to four treatments groups with six replicates of 15 chicks each. The broilers were randomly subjected to one of the following treatments for 28 days: control group (group1, fed a basal diet) and three treatments (group 2, 3, 4) fed the basal diet supplemented with 100, 200, or 300 mg/kg Bacillus coagulans , respectively). The results showed that for 28 days, compared with the control diet, the dietary addition of 200 mg/kg Bacillus coagulans significantly decreased the feed/gain ratio (F/G) (p<0.05), improved the thymus index, spleen index and bursa index (p<0.05), increased the villus height to crypt depth ratio (V/C) in the duodenum (p<0.05), increased the number of secretory immunoglobulin (sIgA) positive cells ( p<0.05). The dietary addition of 200 mg/kg Bacillus coagulans promoted a significant increase in Lactobacillus spp. populations and suppressed Escherichia coli replication in cecum, compared with the control (p<0.05). Moreover, the dietary addition of 200 mg/kg Bacillus coagulans also significantly enhanced the levels of interferon alpha (IFNα), toll-like receptor (TLR3), and melanoma differentiation-associated protein 5(MDA5) in the duodenum (p<0.05). In conclusion, the dietary addition of Bacillus coagulans significantly improved broiler performance, and enhanced the intestinal mucosal barrier and immune function. The optimal dosage of Bacillus coagulans for yellow broilers was determined as 2×108 cfu/kg.
Abstract in English:ABSTRACT Laser beak trimming is a promising alternative to conventional hot-blade beak trimming as it is less painful and provides better beak uniformity and better animal welfare. In this study, laser vs. hot-blade beak trimming were compared in 400 Hy-line Brown pullets between 2-16 weeks of age. At 7 days of age, birds were distributed according to a completely randomized design into two treatments, with 10 replicates (pens) of 20 birds each. Birds and feed offer and residues were weekly weighed to determine weight gain, feed intake, and feed conversion ratio. In weeks 4, 8, 12, and 16 weeks, one bird per experimental unit was sacrificed to measure the development of the heart development, liver, proventriculus, gizzard, small intestine, and bursa. And of the oviduct in week 16. Pullers submitted to laser beak trimming presented higher weight gain and weekly feed intake, and better feed conversion ratio during the evaluated period. There was no influence of beak trimming methods on the development of the digestive organs, bursa or oviduct. Laser beak trimming can be used as an alternative to hot-blade beak trimming of commercial brown layers.
Abstract in English:ABSTRACT Background: Eggshell ultrastructure organization, including effective layer thickness, mammillary layer thickness, and average size of mammillary cones, is important for breeding and significantly influences eggshell mechanical properties. Several matrix proteins were known to be important in eggshell formation. However, the proteins and variations that determine eggshell ultrastructure organization are not known. Results: In this study, 17 single-nucleotide polymorphisms of three major genes in a hen population using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Five single-nucleotide polymorphisms with a very low minor allele frequency (< 1%) were excluded from further analysis. The remaining 12 single-nucleotide polymorphisms in Hardy-Weinberg equilibrium were used for analysis of associations with eggshell ultrastructure organization. Associations were found for (i) ovocleidin-116 with effective layer thickness (EFF), mammillary layer thickness (MAM), and average size of mammillary cones (SMAM); (ii) ovalbumin with eggshell thickness (ESH), effective layer thickness, and density of the mammillary cone (DMAM); and (iii) calmodulin1 with density of the mammillary cone. Conclusions: The single-nucleotide polymorphisms identified in the present study may be used as potential markers to improve eggshell quality.
Abstract in English:ABSTRACT The present study investigated the effectiveness of a single Salmonella prevention and control program applied in two different processing plants, located in the states of Mato Grosso do Sul (plant A) and Santa Catarina (Plant B), belonging to the same company, and identified Salmonella strain subtypes isolated from broilers, carcasses before and after chilling, and frozen chicken breasts. The Salmonella prevention and control program was 90% effective in plant A and 100% in plant B, considering a level of 10% positive samples per frozen chicken breast batch acceptable. A total of 128 strains were serotyped, being 10 from drag swabs, 31 from cloacal swabs, 83 from carcasses, and 4 from frozen chicken breasts. After serotyping analysis, 30 strains isolated at different processing steps and drag swabs, and three Salmonella Minnesota strains isolated in 2012 in plant A, were genotyped by PFGE. In plant A, the most frequently strain isolated was Salmonella Minnesota (90.35%), followed by Salmonella Newport (8.77%), and in Plant B, Salmonella Senftenberg (80%). Salmonella Minnesota strains were differentiated by PFGE into 19 pulsotypes distributed in three clusters. The phenotypic identification by serotyping of four strains diverged from their PFGE genotypic results. Most Salmonella Minnesota strains genotyped in plant A and the strains isolated from environmental samples in 2012 in the same broiler processing plant belong to a single cluster, confirming the dominance and persistence of this clone over time.
Abstract in English:ABSTRACT Under routine feeding conditions, 1-day-old male chicks were randomly divided into control group (CK), heat-stress group (HS), and GABA + heat stress group (GABA+HS). The thymus contents of IL-1, IL-2, TGF-β1, IFN-γ, GH and HSP70 were determined by enzyme-linked immunosorbent assays. The results showed that: (1) IL-1 and TGF-β1 contents of HS group were significantly lower than those of the CK group (p<0.05), and those of the GABA+HS group were significantly higher relative to the HS group (p<0.05); (2) IL-2 and IFN-γ contents of the HS group were significantly higher than those of the CK group (p<0.05), and those of the GABA+HS group were significantly lower relative to the HS group (p<0.05);(3) the thymus GH content of all three groups first increased and then decreased. The expression levels GH of the HS and GABA+HS groups were significantly lower than CK group (p<0.05); and (4) HSP70 expression levels in the thymus were significantly higher in the HS and GABA+HS groups relative to the CK group (p<0.05). These results indicate that heat stress affected thymus development, immune functions, and overall growth of chickens. Furthermore, it was shown that feeding GABA may significantly improve the immune responses of heat-stressed chickens by increasing the expression levels of IL-1 and TGF-β1, and effectively alleviate the negative effects of heat stress on thymus development by changing HSP70 expression and GH secretion.
Abstract in English:ABSTRACT Quantitative RT-PCR was applied to measure the relative expression levels of the adipose differentiation-related protein (ADFP) gene, fatty acid transport protein 1 (FATP1) gene and apolipoprotein B (ApoB) gene in subcutaneous fat, abdominal fat, liver and muscle at five growth stages (28, 49, 70, 91 and 112 d) to determine the effect of the expression ofthese genes on fat deposition in Daweishan Mini chickens.The relative expression of ADFP gene mRNA in the abdominal fat andthe liver was significantly different between 49 d and 70 d (p<0.05). The relative ApoB gene expression on 91d was higher in the liver, followed by muscles,subcutaneous fat, and abdominal fat, and was significantly higher in the liver than in the other three tissues. FATP1 gene expression in the liver presented a significant positive correlation with subcutaneous fat thickness (p<0.05). The results of this study suggest that the three genes may control the fat development in Daweishan Mini chicken.
Abstract in English:ABSTRACT The aim of this study was to evaluate the effect of adding zinc (Zn) mineral supplements from organic (ZnGly) and inorganic (ZnO) sources to growing male Ross 308 chickens on the mechanical, geometric, and histomorphometrical parameters of long bones. A corn-soybean meal basal diet was supplemented with Zn at 50 or 100 mg·kg-1 of a premix, except the control group (0 suppl). The serum concentration of insulin-like growth factor 1 was higher in the ZnGly50 group compared with the control group. Positive influence of Zn on the femur is highlighted when considering the significant increase in parameters such as mean relative wall thickness, and maximum elastic and ultimate strengths after Zn administration. Zinc supplementation did not affect tibial parameters. The histomorphometric analysis showed a positive impact of Zn supplementation (irrespective of source and level) on femoral trabecular thickness. Rapid loss in actual bone volume in tibial metaphyseal trabeculae was observed with ZnGly at 50 mg·kg-1. In conclusion, this study showed that dietary Zn supplementation positively influences bone mechanical properties, confirming its beneficial effect on the development of the skeletal system and bone tissue of broilers tested for a nutritional-osteoporotic factor. Adverse health effects in trabecular bone as a result of the use of Zn at 50 mg·kg-1 of the premix show that supplementing Zn at the recommended dose (100 mg·kg-1) is essential.