Polymorphism and expression of insulin-like growth factor 1 (IGF1) gene and its association with growth traits in chicken

1. The objectives of the study were to detect polymorphism in the coding region of the IGF1 gene, explore the expression profile and estimate association with growth traits in indigenous and exotic chickens.

2. A total of 12 haplotypes were found in Cornish, control layer and Aseel breeds of chicken in which the h1 haplotype was most frequent.

3. Nucleotide substitutions among haplotypes were found at 21 positions in the IGF1 gene in which 4 substitutions resulted in non-synonymous mutations in the receptor binding domain of the IGF1 protein.

4. The haplogroup showed a significant effect on body weight at 24 and 42 d of age in the control layer line, body weight at 42 d and daily weight gain between 29 and 42 d in the control broiler line, daily weight gain between 29 and 42 d in Cornish, and body weights at 42 d as well as daily weight gain between 29 and 42 d in Aseel birds.

5. IGF1 expression varied among the breeds during embryonic and post-hatch periods. The expression among the haplogroups varied in different chicken tissues. The effect of haplogroup on myofibre number in pectoral muscle was non-significant, although there was significant variation in numbers between d 1 and d 42, and between broiler and layer lines.

6. It was concluded that the coding region of the IGF1 gene was polymorphic, expressed differentially during the pre-hatch and post-hatch periods, and haplogroups showed significant association with growth traits in chicken.     

Effect of chicken meat replacement by spent laying hen meat on physicochemical properties and sensorial characteristics of fresh sausage

1. Sausages were used to assess the effects of chicken meat replacement by spent laying hen meat on the quality parameters and sensorial properties.

2. Five formulations were developed: control (CON) containing 100% chicken meat and 4 levels of chicken meat replacement with spent laying hen meat: 25% (T25), 50% (T50), 75% (T75) and 100% (T100).

3. Appearance, texture, succulence, flavour and overall consumer acceptance were analysed. Parameters such as moisture, ash, fat and protein content, pH, cooking loss and colour parameters (lightness (L*), redness (a*), yellowness (b*)) were analysed, as well as the texture properties (hardness, elasticity, cohesiveness and chewiness).

4. Statistical analysis did not reveal significant (P > 0.05) differences in chemical composition and colour parameters among formulations. On the other hand, CON treatment showed the lowest (P < 0.05) cooking loss (20.45%) that increased as spent laying hen meat increased in the formulation (24.92% vs. 27.65% vs. 28.12% vs. 33.05%, for T25, T50, T75 and T100 batches, respectively).

5. Regarding textural parameters, T75 and T100 formulations presented higher (P < 0.05) hardness and chewiness compared to the other ones.

6. Concerning to sensorial characteristics, the T100 formulation presented the lowest average scores (P < 0.05) for all attributes studied. However, the other batches (T25, T50 and T75) did not show significant differences for appearance, texture, succulence, flavour and overall acceptability attributes compared with the CON formulation.

7. The results indicated that the substitution of up to 75% of chicken meat by spent laying hen meat did not decrease the sensory acceptance of the sausages by consumers, demonstrating that this level of substitution in sausages allows better use of spent laying hen meat.     

Genetic effects of vascular endothelial growth factor and its receptor 2 on feather maturity in three chicken breeds

1. The goal of the current study was to evaluate the genetic effects of the vascular endothelial growth factor (VEGF) and its receptor (VEGFR-2) on feather maturity in the Qingyuan partridge chicken, Guangxi sanhuang chicken and Princess chicken.

2. Both SSCP-PCR and qPCR were employed to detect the polymorphism and gene expression of the VEGF and VEGFR-2 genes.

3. Four SNPs were identified in the VEGFR-2 gene. Exon10-A69G was associated with feather maturity (P < 0.01). Princess chickens with the genotype EF had higher feather maturity scores (P < 0.01). Higher expression levels of VEGF and VEGFR-2 were detected in the immature feather group of Qingyuan partridge chickens, especially in the skin.

4. The VEGF and VEGFR-2 genes play critical roles in feather maturity. In addition, exon10-A69G and genotype EF in the Princess chicken could potentially be utilised as genetic markers to improve efficiency in breeding.     

Tall oil fatty acid inclusion in the diet improves performance and increases ileal density of lactobacilli in broiler chickens

1. Studies were conducted with tall oil fatty acids (TOFA) to determine their effect on broiler chicken performance and ileal microbiota. TOFA, a product originating from coniferous trees and recovered by fractional distillation of side-streams from pulp production, mainly comprises free long-chain fatty acids (~90%) and resin acids (~8%). Conjugated linolenic acids and pinolenic acid are characteristic fatty acid components of TOFA.

2. TOFA products at 750 mg/kg feed were tested in two 35-day broiler chicken trials, each using a wheat soya-based diet and with 12 replicate pens per treatment. In both trials, TOFA improved body weight gain at all time points (P < 0.001) and feed conversion efficiency during the first 21 days (P < 0.01). Two different dry TOFA formulations (silica carrier and palm oil coating) were tested and showed performance effects similar to liquid TOFA.

3. Ileal digesta of the broiler chickens was analysed for total eubacteria, Lactobacillus spp., Enterococcus spp., Escherichia coli and Clostridium perfringens on days 14 and 35. TOFA significantly increased total eubacteria and lactobacilli density on day 14 (P < 0.05). There was a significant positive correlation between these bacterial groups and broiler body weight on day 14 (P < 0.01).

4. A numerical reduction in C. perfringens was observed. In vitro growth inhibition studies showed that C. perfringens was strongly inhibited by 10 mg/l TOFA (P < 0.001), while common lactobacilli were resistant to >250 mg/l. The in vitro results were thus in line with in vivo observations.

5. The mechanisms behind the bacterial shifts and their role in performance improvement are unknown. Further purification of TOFA components is needed to identify the effective agents.     

The occurrence of giant fibres in different muscles of two chicken genotypes

1. The occurrence of Giant Fibres (GF) in three muscles (Pectoralis major (PM), Iliotibialis lateralis and Semimembranosus) with different types of energy metabolism was studied in slow- and fast-growing chicken strains.

2. A total of 20 one-day-old Leghorn chicks (slow-growing) and 20 broiler (Ross 508) chicks (fast-growing) were reared to 100 and 45 d, respectively.

3. A small percentage of GF was seen in pre rigor muscle samples even at 3 min post mortem in both genotypes and in all muscle types studied.

4. From 3 min to 24 h post mortem GF increased both in Leghorn and broiler chickens but to a different extent according to muscle type and genotype.

5. The highest GF 24 h post mortem value was found in the PM muscles belonging to the fast-growing broiler line.

6. It was concluded that every type of muscle can develop GF, but this phenomenon is more evident in the PM especially in animals selected for increased growth rate.     

Five alternative splicing variants of the TYR gene and their different roles in melanogenesis in the Muchuan black-boned chicken

1. The TYR gene encodes tyrosinase, a multifunctional enzyme that is essential for melanin biosynthesis in melanocytes. This experiment involved the cloning and characterisation of the TYR gene in chicken. Five alternative splice variants were identi?ed in the black feather bulb and designated as TYR-AS1, TYR-AS2, TYR-AS3, TYR-AS4 and TYR-AS5.

2. Among the 11 chicken tissues examined, the feather bulb, comb and skin showed higher levels of all TYR variants. All TYR variants were expressed at significantly different levels in black and white feather bulbs (P < 0.05) and may be involved in melanin formation in plumage. Only TYR-AS1, which plays an important role in muscle melanogenesis, was significantly differentially expressed between black and white muscle (P < 0.01). All TYR variants were expressed at significantly different levels in black and white skin (P < 0.01).

3. The mRNA expression levels of the 5 variants were closely associated with skin melanogenesis in the chicken. These findings provide new clues to the molecular mechanism of melanin formation in the Muchuan black-boned chicken.     

Effect of supplementing vitamin E analogues on post-thaw semen parameters and fertility in chicken

1. The effect of supplementing water-soluble vitamin E analogues 6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (trolox) and butylated hydroxy toluene (BHT) was studied in two separate experiments.

2. In the first experiment, trolox was supplemented at 0.2 mM, 0.4 mM and 0.8 mM concentrations along with N-methylacetamide (MA; 12% final concentration) and semen was cryopreserved in 0.5 ml French straws. Different semen parameters and fertility were assessed from post-thaw samples.

3. Sperm motility, live sperm, and mitochondrial activity were significantly lower (P < 0.05) in cryopreserved semen. Lipid peroxidation (LPO) was significantly higher (P < 0.05) in cryopreserved semen that was reduced by trolox supplementation. The treatment containing trolox at 0.2 mM concentration produced significantly higher (P < 0.05) fertility compared to unsupplemented cryopreservation treatment.

4. In the second experiment, BHT was supplemented at 0.25 mM, 0.5 mM, and 1 mM concentrations along with MA during semen cryopreservation.

5. Sperm motility, live sperm and MTT dye reduction test were significantly lower (P < 0.05) in cryopreserved semen. These parameters declined with increasing BHT concentration. Abnormal sperm was significantly higher (P < 0.05) in the BHT supplemented treatments. The sperm chromatin dispersion (SCD) test was significantly higher (P < 0.05) in cryopreserved samples and was highest in samples supplemented with 0.5 mM and 1 mM BHT. The percentage fertility was significantly lower (P < 0.05) in cryopreserved semen and BHT supplementation did not improve fertility.

6. In conclusion, trolox supplementation at 0.2 mM concentration during semen cryopreservation improved fertility, whereas BHT supplementation resulted in a decline in post-thaw semen parameters.     

Effects of heat-treated hempseed supplementation on performance,egg quality,sensory evaluation and antioxidant activity of laying hens

1. This study was conducted to determine the effects of raw and heat-treated hempseed (HHS, Cannabis sativa L.) on performance, egg quality and antioxidant activity in laying hens.

2. A total of 108 laying hens, aged 36 weeks, were divided into three treatment groups with 12 replicates and each replicate contained three laying hens. The treatments were as follows: (1) Control (no hempseed), (2) 15% raw hempseed (RHS) in diet and (3) 15% HHS in the diet. Experiments lasted for 12 weeks.

3. Feed intake of the RHS group was lower than those of the control and HHS groups. Egg weight, egg mass, shell weight, shell surface area and shell thickness of the HHS group were significantly (P < 0.05) higher than that of the RHS group. Roche (DSM) colour fan values of the RHS group were higher than that of the HHS group (P < 0.01).

4. Palmitic, palmitoleic and oleic acids of egg yolk were significantly (P < 0.05) decreased in the RHS and HHS groups; however, linoleic, α-linolenic and docosahexaenoic acids (DHA) of egg yolk increased (P < 0.05) for both treatment diets compared to the control group.

5. Both RHS and HHS supplementation to layer diets did not influence malondialdehyde (MDA) and superoxide dismutase (SOD) activity and blood lipid profile.

6. It was concluded that HHS was superior in improving the egg quality of laying hens as compared to the RHS.     

Possible role of central interleukins on the anorexigenic effect of lipopolysaccharide in chicks

1. The purpose of the present study was to determine if central interleukin-1β (IL1β), interleukin-6 (IL6) and interleukin-8 (IL8) affect feeding behaviour in chicks (Gallus gallus) and examine if central interleukins are related to the lipopolysaccharide (LPS)-induced anorexia.

2. Intra-abdominal (IA) injection of LPS significantly suppressed feeding behaviour and significantly increased mRNA expression of IL1β and IL8 in the diencephalon when compared to the control group, while IL6 tended to be increased.

3. Intracerebroventricular (ICV) injection of 200 ng IL1β significantly decreased food intake at 60 min after the injection while IL6 and IL8 had no effect.

4. IA injection of these ILs (200 ng) had no effect on food intake in chicks.

5. ICV injection of 200 ng IL1β did not affect water intake and plasma corticosterone concentration, suggesting that central IL1β might not be related to the regulation of drinking behaviour and the hypothalamus–pituitary–adrenal axis.

6. The present study demonstrated that central IL1β but not IL6 and IL8 might be related to the inhibition of feeding in chicks.     

Growth performance and meat quality of broiler chickens supplemented with Rhodopseudomonas palustris in drinking water

1. The effect of the bacterium, Rhodopseudomonas palustris, on the growth performance and meat quality of broiler chickens was investigated.

2. A total of 900-d-old Arbor Acres broilers were allocated to three experimental treatments for 6 weeks. Chicks were administered with R. palustris in drinking water as follows: (i) control group without R. palustris; (ii) treatment 1 (R1) with R. palustris of 8 × 10⁹ cells per chick per day in drinking water; (iii) treatment 2 (R2) with R. palustris of 1.6 × 10¹⁰ cells per chick per day in drinking water.

3. The results showed that, compared with that of control, both groups of R. palustris treatment increased daily weight gain and improved feed conversion ratio of broiler chickens significantly during the whole growing period of 6 weeks.

4. Both total and glutamic acid contents of chicken breast fillet in R. palustris treatment R2 were higher, while the fat content was lower, than those of the control group. Furthermore, R. palustris treatments also improved sensory attributes of chicken breast fillet.

5. As a probiotic providing rich nutrients and biological active substances, R. palustris administration in drinking water displayed a growth promoting effect and improved meat quality of broiler chickens.     

Influence of graded inclusion of white lupin (Lupinus albus) meal on performance,nutrient digestibility and ileal viscosity of laying hens

1. The aim of this study was to investigate the effect of white lupin (Lupinus albus) meal (WLM) addition on the intestinal viscosity, bird performance and nutrient utilisation of laying hens.

2. The experiment was conducted with 360 laying hens aged 21 weeks fed one of 6 treatments, including a corn-soybean meal control diet (CON) and 5 experimental diets containing 60, 120, 180, 240 and 300 g/kg WLM.

3. A linear increase in feed intake (p < 0.001) was observed with higher levels of WLM from 0 to 300 g/kg. Laying rate decreased quadratically (p < 0.05) and egg weight (at 6th, 12th and 18th weeks of the trial) decreased linearly with WLM inclusion from 0 to 300 g/kg. Birds fed 60 g/kg or more of WLM laid lighter eggs (p < 0.05) than CON hens. When 240 g/kg or more WLM was included into the diet, laying rate was affected negatively (p < 0.05).

4. As WLM increased from 0 to 300 g/kg, apparent metabolisable energy and pre-caecal digestibility of dry matter and crude protein decreased quadratically (p < 0.05). When 300 g/kg of WLM was used, there was a tendency (p < 0.1) to decrease pre-caecal starch digestibility. WLM dose exerted a quadratic effect (p < 0.05) on total sialic acid excretion. As WLM increased, the viscosity of ileal digesta linearly increased (p < 0.05).

5. In the 6th and 12th weeks of the experiment (p < 0.05), eggshell thickness decreased linearly when 240 g/kg of WLM was added. At the 6th, 12th and 18th weeks, a linear decrease in eggshell content was observed (p < 0.05) after WLM addition.

6. In conclusion, the graded inclusion of WLM into laying hens’ diets resulted in depressed performance, AME_N and eggshell quality.     

Improved early performance of turkey poults given an Aloe ferox leaf extract with bentonite

1. AT-402 (20 g/kg), a proprietary blend of Aloe ferox leaf extract and calcium bentonite, had no adverse effect on poult body weights at 3 weeks of age.

2. Lower body weights and lower feed consumption were observed in 4-week-old poults given 10 and 20 g/kg of AT-402 compared to poults given 0 or 5 g/kg.

3. Floor-reared poults, given either 5 or 10 g/kg AT-402 to 4 weeks of age, were significantly heavier than controls (0 g/kg AT-402), and feed conversion ratios for AT-402 given poults were improved.

4. Xylose uptake in 5 g/kg AT-402-fed poults was significantly greater than in poults given AT-402 at 0 and 10 g/kg, reflecting increased body weights of 5 g/kg AT-402-fed poults.

5. Delayed access by poults to the AT-402 until 10 d of age also improved 4-week body weights, suggesting that the AT-402 might improve performance as soon as it is given.

6. AT-402 at 5 g/kg was most efficacious as demonstrated by improved body weights and feed conversions.     

Different susceptibility to fatty liver-haemorrhagic syndrome in young and older layers and the interaction on blood LDL-C levels between oestradiols and high energy-low protein diets

1. The objective of the study was to investigate the susceptibility of young and older laying hens to fatty liver-haemorrhagic syndrome (FLHS) and to evaluate the reliability of different blood lipid fractions for predicting or diagnosing FLHS.

2. Forty young hens and 40 older hens were caged individually. Each group of hens was randomly allotted to four treatments for 21 days: either a control, an oestradiol group, a high energy-low protein diet (HELPD) group or a HELPD + oestradiol group. Blood levels of oestradiol, triglyceride (TG), cholesterol (CHOL), high density lipoprotein-cholesterol (HDL-C) and low-density lipoprotein-cholesterol (LDL-C), liver total lipids, hepatic haemorrhagic scores and productive performance were assessed.

3. In older hens, β-oestradiol increased (P < 0.05) liver total lipids, hepatic haemorrhagic scores and the incidence of FLHS but reduced (P < 0.05) productive performance; however, such changes were not observed in young hens.

4. In two groups of hens, serum TG, CHOL and HDL-C levels were increased (P < 0.001) by β-oestradiol. Hens with FLHS had higher serum TG, CHOL and HDL-C (P < 0.001) than non-FLHS birds in the older layer group of hens.

5. An interaction (β-oestradiol × HELPD) (P < 0.05) for LDL-C levels was observed in both groups of hens. In young hens, β-oestradiol induced a decrease (P = 0.004) in serum LDL-C levels but the effect was attenuated by HELPD. In older hens, HELPD caused an increase (P = 0.02) in serum LDL-C although the effect depended on the presence of β-oestradiol.

6. In conclusion, older layers were more susceptible to FLHS than young layers after oestradiol treatment. Blood TG, CHOL and HDL-C rather than LDL-C levels can be used as a prediction tool for the overall susceptibility to FLHS in older rather than young layers. There were interactions between oestradiol and HELPD on blood LDL-C levels in laying hens.     

Electroencephalographic assessment of concussive non-penetrative captive bolt stunning of turkeys

1. The aim of this study was to evaluate the electroencephalographic (EEG) and behavioural responses of turkeys stunned with three different concussive non-penetrative captive-bolt guns prior to slaughter.

2. A total of 31 slaughter weight ex-breeding female turkeys (29 weeks of age; mean body weight 13.32 ± SD 0.65 kg) were stunned with the Cash Poultry Killer (CPK) (n = 10), Turkey Euthanasia Device (TED) (n = 10) and Zephyr EXL (n = 11).

3. Mean peak kinetic energy was highest for the CPK compared to the TED and Zephyr EXL (75.9 ± 4.5, 28.4 ± 0.4 and 24.4 ± 0.7 J, respectively).

4. A total of 29 (94%) of the turkeys were rendered unconscious following captive bolt stunning, with total power of the EEG (Ptot) significantly reduced from baseline values (reductions of 67% CPK, 84% TED and 76% Zephyr EXL, p < 0.01) and waveforms becoming isoelectric after periods of transitional EEG. However, two birds shot with the CPK and Zephyr EXL had periods of behavioural/reflexes (rhythmic respiration, nictitating membrane reflex, neck tension) and EEG activity (43–47 and 36–60 + s after the shot, respectively) indicating incomplete concussion and return of consciousness. In one bird, the shot was incorrectly positioned (Zephyr EXL), while the other appeared to be related to a defective cartridge (CPK).

5. In conclusion, all three captive bolt gun models were effective in producing unconsciousness in turkeys, provided they were positioned correctly and power loads performed according to their specifications.     

Physical and chemical properties of meat from scavenging chickens and helmeted guinea fowls in response to age and sex

1. The effects of age and sex on body weight, carcass traits, physical and chemical properties of breast muscle from chickens and helmeted guinea fowls managed under village free-range conditions were assessed in random samples of 48 guinea fowls and 48 chickens obtained from local markets.

2. Guinea fowls had higher body weight, hot carcass weight, cold dressed weight and breast weight than chickens.

3. Guinea fowls had more dry matter, protein and less fat than chickens. Ash content did not differ between guinea fowls and chickens. Protein and fat increased, whereas dry matter and ash decreased with age (P < 0.05)

4. Chicken meat was lighter, less red and more yellow than guinea fowl meat. Cooking loss was higher in guinea fowls, male and grower birds than chickens, females and adult birds, respectively. Shear force was affected by age, as mature birds had a higher value than growers.

5. Guinea fowl carcasses contained more meat that was leaner, higher in protein and redder compared with chicken meat. As age increased the meat increased in protein and fat content and shear force, whereas colour became darker, redder and yellower.     

Prevalence and antimicrobial resistance of Arcobacter species isolated from poultry meat in Iran

1. The objective of this study was to determine the prevalence and antimicrobial resistance of Arcobacter spp. isolated from different species of retail poultry meat in Iran.

2. From August 2012 to April 2013, a total of 540 raw poultry meat samples from chicken (n = 100), turkey (n = 100), quail (n = 100), partridge (n = 80), duck (n = 50), ostrich (n = 60) and geese (n = 50) were purchased from randomly selected retail outlets in Shahrekord, Isfahan, Sari and Rasht, Iran.

3. Using culture techniques, 71 of 540 poultry meat samples (13.1%) were positive for Arcobacter spp. The highest prevalence of Arcobacter spp. was found in chicken meat (28.0%), followed by quail (12.0%), duck (11.4%), turkey (11.0%), geese (8.0%), partridge (7.5%) and ostrich (3.3%) meat. The number of A. butzleri isolated from poultry meat samples (90.1%) was significantly higher than A. cryaerophilus (7.1%) and A. skirrowii (2.8%). Significantly more poultry meat samples were found to contain Arcobacter spp. by the PCR assay than by the culture method.

4. Susceptibilities of Arcobacter isolates were determined for 14 antimicrobial drugs using the disk diffusion method. All of the 71 Arcobacter isolates tested were resistant to one or more antimicrobial agents. Resistance to cephalothin and vancomycin (95.8%) was the most common finding, followed by resistance to methicillin, azithromycin and ampicillin. All Arcobacter isolates were susceptible to gentamicin, streptomycin, tetracyclin and kanamycin.

5. The results of this study indicated the importance of poultry meat, especially chicken meat, as potential sources of Arcobacter spp. infection in people. Furthermore, the strains indicated resistance to a broad spectrum of antibiotics.