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.     

Influence of citrus flavonoids on laying hen performance,inflammatory immune response,egg quality and yolk oxidative stability

1. The objective of this study was to investigate the effects of dietary supplementation with natural flavonoids (naringin and hesperidin) on laying hens’ performance, cellular immunity and egg quality parameters.

2. A total of 72 individually caged laying hens were allocated into 1 of 6 treatment groups: a control (C) group that was fed with a basal diet and groups that were offered the same diet further supplemented with hesperidin at 0.75 g/kg (E1), or 1.5 g/kg (E2), or naringin at 0.75 g/kg (N1), or 1.5 g/kg (N2) or α-tocopheryl acetate at 0.2 mg/kg (VE) for 67 d.

3. Supplementation with naringin or hesperidin did not affect the performance and egg quality (P > 0.05) apart from an improvement in the yolk colour that was more orange in naringin and hesperidin groups in comparison to the controls (P-linear < 0.05). Egg yolk and plasma cholesterol levels were not affected by citrus flavonoids (P-linear > 0.05).

4. Inflammatory immune response, measured by phytohaemagglutinin skin test (PHA), was suppressed in laying hens that were fed with either naringin (P-linear < 0.05) or hesperidin (P < 0.05). Egg yolk oxidative stability was improved from the 4th d after naringin or hesperidin supplementation. This beneficial effect was comparable to that of α-tocopheryl acetate and was observed in eggs that were stored for up to 120 d.

5. In conclusion, naringin and hesperidin may favourably prolong the shelf life of eggs, appear to possess anti-inflammatory properties and could improve the yolk colour without any side effects on the performance or egg quality traits.     

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.     

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.     

High,low, or familiar? Nest site preferences of experienced laying hens

1. The aim of this study was to investigate which nest heights are preferred by laying hens in the absence of familiar nest locations and whether preferred nest heights are more attractive than a familiar location. In two experiments, a total of 108 hens of four different layer breeds, which were at least 50 weeks of age, were studied.

2. In the first experiment, hens were given individual free choice between nests for 1-week at four different heights (0 cm, 39 cm, 78 cm, and 117 cm above ground). Hens of the four breeds differed in their nest height preferences (P = 0.0013). However, hens of three breeds preferred ground level nests (P < 0.007) and the fourth line showed an equal preference for the ground level and level three, the latter level corresponding to the height of the nests in their home compartments.

4. In the second experiment, hens from the four breeds were given a choice between ground level nests and nests at a familiar location, i.e. at the same location as in their home compartment. Hens of all strains preferred the familiar nest location (P = 0.002) and preferences did not differ between strains (P = 0.77).

5. Laying hens seem to prefer nests at ground level in the absence of a familiar nest. However, if possible, experienced 50 week old hens continue to use a familiar nest location instead of a ground nest location. The results are discussed with respect to a potential primary preference that may be modifiable by experience and with respect to possible relevance in commercial housing.     

Effects of short intermittent lighting on food consumption and performance of dwarf broiler breeders and progeny

1. Two hundred and sixty four dwarf broiler breeder hens were subjected to ad libitum or restricted feeding and to four lighting patterns: 15L (bright light):9D (dark), 15L:9d (dim light), 2L:10d: 1L:11d, (0.5L:3.5d) × 6.

2. Breeder hens fed ad libitum and subjected to either conventional or intermittent lighting ingested respectively, 25 g and 14 to 17 g more than hens restricted to 115 g/d.

3. Body weight was greater in hens fed ad libitum irrespective of the lighting pattern and of the amount of food intake.

4. Persistency of egg production was impaired by intermittent lighting.

5. Ad libitum feeding reduced egg fertility. The decrease was larger in breeder hens on intermittent lighting.

6. Hatchability was increased in hens submitted to the symmetrical lighting pattern (0.5L:3.5d).

7. Egg and chick weights were higher in hens fed ad libitum.

8. Shell index and shell breaking strength increased in restricted hens on the intermittent lighting pattern (0.5L:3.5d) × 6.

9. The best performance was obtained in restricted hens on the conventional lighting pattern.     

Effects of dietary supplementation of choline and carnitine on growth performance,meat oxidative stability and carcass composition of broiler chickens fed diets with different metabolisable energy levels

1. This study was conducted to investigate the effects of two lipotropic factors (choline and carnitine) on growth performance, oxidative stability of leg and breast muscles and carcass characteristics in broiler chickens fed diets differing in metabolisable energy (ME) levels.

2. A total of 540 one-d-old Ross 308 broiler chicks were allotted to 9 experimental diets, including three ME levels (control, or 0.42 or 0.84 MJ/kg higher ME) and three types of supplemental lipotropic factors (control, 1000 mg/kg of choline or 100 mg/kg of carnitine) as a 3 × 3 factorial arrangement of treatments. Average daily feed intake (ADFI), average daily gain (ADG) and feed conversion ratio (FCR) were recorded during the starter (1–14 d of age), grower (15–28 d of age) and finisher (29–42 d of age) periods.

3. Results showed that the increase in dietary ME level had no impact on ADFI during the starter and grower periods. In the finisher period, increasing dietary ME decreased (P < 0.001) ADFI. Raising dietary ME level by 0.84 MJ/kg resulted in the greater ADG during the grower (P < 0.05) and finisher (P < 0.001) periods. Moreover, an improvement in FCR was observed with feeding the +0.84 MJ/kg diet. Dietary supplementation of lipotropic factors improved FCR values in birds fed the control and +0.84 MJ/kg diets during the grower and finisher periods (P < 0.01).

4. Dietary supplementation of both choline and carnitine increased (P < 0.05) moisture content of leg muscle, although malondialdehyde content of leg muscle was decreased (P < 0.01) in the presence of both lipotropic factors. Dietary supplementation of carnitine decreased (P < 0.01) leg fat content, and this effect was more obvious with higher ME levels, giving a significant ME × lipotrope interaction (P < 0.05). Higher dietary ME level (+0.84 MJ/kg) reduced (P < 0.05) protein content of breast muscle, but this factor was increased (P < 0.05) by dietary supplementation of choline.

5. Although dietary ME level had no marked effect on carcass yield and internal organ weight, supplemental choline increased (P < 0.01) carcass yield.

6. The results from this trial indicated that dietary supplementation with lipotropic factors can improve feed efficiency in high energy diets. In addition, oxidative stability of leg/breast muscles was improved as a result of dietary supplementation with choline or carnitine.     

Influence of bone meal degelatinisation and calcium source and particle size on broiler performance,bone characteristics and digestive and plasma alkaline phosphatase activity

1. The current experiment was performed to elucidate the effects of degelatinised bone meal (DBM) in combination with different particle sizes of limestone or oyster shell on broiler performance, bone characteristics and digestive and plasma alkaline phosphatase (ALP) activity.

2. Treatments were applied as a 3 × 3 factorial arrangement with three sources of P (DCP, bone meal and DBM) and three particle sizes (50, 100 and 200 µm) of limestone. Chickens were given either DCP or DBM with oyster shell (523 µm), resulting in a total of 11 treatments with 5 replicates of 8 chicks.

3. Performance criteria were measured weekly. Tibia strength, ash, calcium (Ca) and phosphorus (P) content and plasma P and Ca concentration along with plasma and intestinal alkaline phosphatase (ALP) activity and P digestibility were measured on d 14 and 28.

4. Body weight and FCR were improved in chicks which were fed DBM or oyster shell in comparison to the DCP and limestone respectively (P ≤ 0.05). Performance was influenced (P ≤ 0.05) by particle size; with coarser particles BW and feed intake were increased (P ≤ 0.05). Tibia shear force and P content were reduced (P ≤ 0.001), whereas tibia shear energy, length, ash and Ca content were increased by substitution of DCP with DBM or bone meal (P ≤ 0.001; P ≤ 0.05). A significant difference was observed in the tibia length between the chicks fed oyster shell or limestone with different particles (P ≤ 0.05). Plasma P concentration was reduced in chicks were fed with DBM, bone meal and lower limestone particle size. Intestinal ALP activity was increased (P ≤ 0.001) in chicks which were fed DBM, bone meal, oyster shell or coarse particles of limestone. The P digestibility in chicks fed bone meal was lower than that of those fed DBM or DCP (P ≤ 0.01). Overall, gelatin removal from bone meal improved broiler bone characteristics through the P digestibility and intestinal ALP activity enhancement.     

Performance and physiological responses of broiler chickens to supplemental guanidinoacetic acid in arginine-deficient diets

1. The present experiment was designed to examine arginine (Arg)-sparing effects of guanidinoacetic acid (GAA) on production performance, intestinal morphology and certain blood parameters in broiler chickens.

2. A total of 300 male broiler chicks (Ross 308) were randomly allotted to 5 dietary treatments in a completely randomised design during 1–15 and 15–35 d rearing periods. Experimental treatments consisted of a basal diet with a reduction in Arg content (CON?; starter: 12.1 g/kg and grower: 11.3 g/kg Arg), a CON? diet supplemented with synthetic Arg equal to the required Arg level (CON+; starter: 13.80 g/kg; grower: 12.37 g/kg) and CON? diet supplemented with three levels of GAA (GAA0.6; GAA1.2; and GAA1.8; g/kg).

3. Supplemental GAA at 0.6 and 1.2 g/kg reduced the adverse effects of the CON? diet on weight gain and feed conversion ratio in the starter period, equal to the effect of CON+ diet. During the entire rearing period, such an effect was only seen for broilers fed CON? diet supplemented with 1.2 and 1.8 g/kg GAA (P < 0.05). Proportional weights of liver and abdominal fat were decreased in birds fed diets containing supplemental Arg and 1.8 g/kg GAA compared to the CON? broilers (P < 0.05). Jejunal villus height and villus height to crypt depth ratio were increased in broilers receiving the CON? diet (P < 0.05). Serum concentration of nitric oxide increased when the CON? diet was supplemented with either Arg or 1.8 g/kg GAA (P < 0.05).

4. Dietary inclusion of GAA had an Arg-sparing effect, whereby 1.2 and 1.8 g/kg of supplemental GAA resulted in greater growth performance during the starter and entire rearing periods, respectively. Supplementation with 1.8 g/kg GAA had significant effects on some carcass and physiological parameters.     

Pasture,multi-enzymes,benzoic acid and essential oils positively influence performance,intestinal organ weight and egg quality in free-range laying hens

1. The objective of this study was to investigate the effect of range type, multi-enzyme applications, and a combination of benzoic acid (BA) and essential oils (EO) on the productive performance, organ weight and egg quality of free-range laying hens.

2. Three hundred laying hens were evaluated for the short-term (6 weeks) and long-term (12 weeks) effects of range type (G = no pasture, P = pasture) and feed additives (T1 = control; T2 = betaglucanase/pectinase/protease; T3 = BA/EO). Body weight, feed intake (FI), feed conversion ratio (FCR), egg production (EP), digestive organ weight, and egg quality (EQ) were evaluated. Data were analysed using SPSS 2.2 in a 2×2×3 factorial arrangement.

3. Hens that ranged on pasture were significantly heavier (2043 g vs. 1996 g; p < 0.001), laid heavier eggs (61.9 g vs. 60.3 g; p < 0.001) and produced darker yolk colour (4.3 vs. 7.0; p < 0.001) compared to hens ranged on gravel. Hens fed T2 were significantly heavier (2050 g) compared to hens fed T1 (2005 g) or T3 (2008 g). Organ weights (gizzard, liver and pancreas) were significantly heavier in hens ranged on pasture (16.8 g/kg BW, 22.3 g/kg BW and 1.89 g/kg BW, respectively) compared to hens ranged on gravel (14.2 g/kg BW, 21.7 g/kg BW and 1.83 g/kg BW, respectively). Over time, body weight (1970–2070 g; p < 0.001) and egg weight (59.5–62.8 g; p < 0.001) increased, FI (123–120 g; p = 0.024) was reduced and FCR (2.36–2.10; p = 0.002) improved

4. In conclusion, hens housed on pasture and fed multi-enzyme supplemented diets had significantly heavier body weight and produced heavier eggs with darker yolk colour. Pasture intake and enzyme supplementation increased digestive organ weight significantly.     

The protein oxidation of soybean meal induced by heating decreases its protein digestion in vitro and impairs growth performance and digestive function in broilers

1. The soybean meal (SBM) was heated at 100°C for 1, 2, 4 and 8 h, respectively, and their resultant oxidative status was evaluated.

2. A total of 400 one-day-old Arbor Acres broilers were randomly divided into 5 treatments with 8 replicates of 10 birds each, and fed with diets containing non-heated SBM (NHSBM) or 1 of 4 heated SBMs (HSBMs, SBMs heated at 100°C for 1, 2, 4 and 8 h, respectively) for 42 d.

3. The contents of carbonyl in the SBMs were both linearly and quadratically increased, whereas the nitrogen solubility index, and in vitro digestibility of crude protein (CP) and dry matter (DM) in the SBMs were both linearly and quadratically decreased as heating time increased (P < 0.05). The concentrations of sulfhydryl and total sulfhydryl in the SBMs were linearly decreased as heating time increased (P < 0.05).

4. The average daily gain was linearly decreased while the feed conversion ratio (FCR) was linearly increased in broilers as heating time of dietary HSBMs increased during both d 22–42 and d 1–42 of study (P < 0.05), though FCR of broilers during d 22–42 study were unaffected when the heating time of dietary HSBMs was 1 h (P > 0.05). The serum glucose concentration and the activity of trypsin at d 42, and the apparent total digestibility of CP and DM were all linearly reduced in broilers when heating time of dietary HSBMs increased (P < 0.05). However, 1 h HSBM has a numerical higher CP and DM digestibility than NHSBM. The serum urea nitrogen contents were both linearly and quadratically increased at both d 21 and 42 (P < 0.05), and relative pancreas weight was linearly increased at d 42 in broilers as heating time of dietary HSBMs increased (P < 0.05).     

Effect of quercetin on performance and egg quality during the late laying period of hens

1. At the end of the peak laying period for fowl, both performance and egg quality decrease markedly. Counteracting either or both of these could, therefore, have significant positive economic implications. Quercetin, a typical representative of the flavonol compounds, has a variety of biological functions. However, there are no reported findings on its use as a feed additive.

2. In this study, we investigated the effects of quercetin on laying rate, egg quality and blood traits associated with egg quality in laying hens (Hessain) during the late laying period and explored the possibility of using quercetin as a functional feed additive.

3. The laying hens (n = 240; 39 weeks old) were randomly assigned to 4 treatments consisting of 6 replicates (n = 10) and were fed with diets containing quercetin at 0, 0.2, 0.4 or 0.6 g/kg.

4. Results showed that laying rate was increased and feed–egg ratio was decreased significantly by 0.2 and 0.4 g/kg quercetin. Compared with controls, Haugh unit, eggshell strength, eggshell thickness and yolk protein were increased, but yolk cholesterol was decreased by quercetin.

5. In conclusion, quercetin was beneficial in improving performance and egg quality. The recommended concentration of quercetin is 0.4 g/kg of the basal diet. At this concentration, increased laying rate, improved egg quality and reduced yolk cholesterol can be expected.     

The effects of boron supplementation of layer diets varying in calcium and phosphorus concentrations on performance,egg quality,bone strength and mineral constituents of serum,bone and faeces

1. A 2 × 3 factorial arrangement of treatments was used to investigate the effects of dietary calcium (Ca), phosphorus (P), and supplemental boron (B) (0, 75, and 150 mg/kg) on the performance, egg quality, bone strength, and mineral constituents in bone, serum and faeces.

2. A reduction by 18% in the dietary Ca-P concentration from the recommended levels for the hen strain reduced (P < 0.01) faecal excretion of ash, Ca and P concentrations, and shear force with stress of the tibia in association with decreased feed intake, whereas improved albumen height and Haugh unit values in the egg.

3. Supplemental B significantly decreased the feed consumption, egg weight and final body weight in hens, as well as the albumen height, but had no effect on either the biomechanical characteristics of bones or the mineral profile of the bones and serum. However, there was a significant increase in the egg production rate and a reduction in the damaged and shell-less egg ratio, and in the feed conversion rate in hens fed adequate Ca-P with 150 mg/kg B compared to those of the unsupplemented controls.

4. The amount of B that accumulated in the bones and serum was correlated with the amount of B consumed. B increased the faecal excretion of ash, Ca and B. In general, dietary variables had no effect on mineral composition of serum and tibia.

5. The magnitude of the response to dietary B was much more pronounced in hens fed a diet deficient in Ca-P with 75 mg/kg B; these hens exhibited a production performance and an egg quality comparable to those given adequate Ca-P with no added B.

6. The data presented in this study describing the measured bone properties did not corroborate the hypothesis that B is a trace element playing an important role in mineral metabolism and bone strength through an interaction with Ca, P and Mg.     

Effects of Saccharomyces cerevisiae extract on haematological parameters, immune function and the antioxidant defence system in breeder hens fed aflatoxin contaminated diets

1. The study was conducted to investigate the efficacy of Saccharomyces cerevisiae extract (SC) on haematological parameters, immune function, and the antioxidant defence system in breeder hens fed a diet contaminated with low level aflatoxin (AF).

2. Forty-eight Ross 308 breeder hens were fed on diets containing AF (0 or 100?µg/kg) and SC (0 or 1?g/kg) in a 2?×?2 factorial arrangement. Red blood cell (RBC), white blood cell (WBC), and platelet counts, differential leucocyte counts, blood CD3⁺, CD4⁺, CD8⁺ and CD5⁺ T cell ratios, phagocytic activity and oxidative burst of heterophils, plasma and liver catalase activity, and malondialdehyde (MDA) and ascorbic acid concentrations were measured.

3. Plasma and liver MDA concentrations increased (P?P?P?=?0·082) in hens fed the contaminated diet. WBC count, monocyte percentage, phagocytic activity and oxidative burst of heterophils increased (P?P?=?0.088) in SC extract supplemented hens. There was a significant interaction between AF and SC on heterophil, lymphocyte, CD5⁺ cell percentages, and plasma catalase activity. Blood heterophil percentage decreased but lymphocyte percentage increased in hens fed on the AF contaminated diet without SC supplementation. SC supplementation counteracted the negative effect of AF on heterophils and lymphocytes. The CD5⁺ cell percentage decreased in unsupplemented hens fed the AF contaminated diet and this negative effect was minimised in SC supplemented hens. Plasma catalase activity increased in SC supplemented hens fed the uncontaminated diet whereas the effect of SC decreased in hens fed the AF contaminated diet.

4. The SC reduced some of the some adverse effects of AF, and improved functions of the non-specific immune system. Therefore, the SC extract which has been used for improving productive performance in birds and mammals may also be useful for modulating some of the effects of a low level, chronic dosage of AF.     

Effect of melamine-contaminated diet on tissue distribution of melamine and cyanuric acid,blood variables,and egg quality in laying hens

1. The aim of the study was to investigate the effect of melamine-contaminated feed (100 mg/kg) on the distribution of melamine and cyanuric acid in the tissues of laying hens. The effect of a 5-week melamine administration in feed on the egg quality and blood variables of layers was also investigated.

2. A total of twenty 36-week-old ISA Brown layers were used in the experiment. The layers were equally divided into an experimental melamine group (n = 10) and a control group without melamine (n = 10). At the end of the experiment, samples of liver, kidney, breast and thigh muscles were collected from all hens and analysed for the presence of melamine and cyanuric acid by gas chromatography and tandem mass spectrometry.

3. Layers receiving the melamine-contaminated diet laid eggs with decreased eggshell strength. The decrease in shell strength was found in weeks 3 and 4 compared to the initial state (week 0) and week 1.

4. Hens receiving the melamine-contaminated diet also exhibited a higher total red blood cell count and lower mean corpuscular haemoglobin compared to the control group. However, melamine at 100 mg/kg feed had no effects on the blood variables of layers.

5. Melamine was detected in all analysed tissues of layers fed on the melamine-contaminated diet, with its mean concentrations decreasing in the following order: kidney (7.43 mg/kg) > breast muscle (3.88 mg/kg) > liver (3.11 mg/kg) > thigh muscle (1.91 mg/kg). The kidney and liver of layers fed on the melamine-contaminated diet also exhibited the presence of cyanuric acid.

6. On the basis of our results, it can be concluded that the biotransformation of melamine into cyanuric acid proceeded mainly in the liver, and cyanuric acid was eliminated in urine.     

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.     

Ipriflavone reverses the adverse effects of a low-calcium diet on the histology of the tibia in caged layers

1. Ipriflavone (IP) has been widely studied in humans and is effective for inhibiting osteoclastic bone resorption and enhancing osteoblastic bone formation. The aim of this study was to investigate the effects of IP on the structural histology and histomorphometric parameters of tibia in laying hens fed on a low-calcium diet.

2. A total of 200 Hy-Line Brown laying hens, 24 weeks of age, were divided randomly into 4 groups which were fed on one of 4 diets (CaN, standard diet; CaL, low-calcium diet; IP1, low-calcium diet + 8 mg/kg of IP; IP2, low-calcium diet + 20 mg/kg of IP) for 60 d after which 10 hens of each group, chosen at random, were killed and the tibiae were processed and assessed under a fluorescent microscope

3. The cortical bone showing resorption cavities had become porous, and medullary bone did not completely fill the marrow cavity in the CaL group compared with the CaN group. However, in the IP2 group, the cortical bone showed a structure comparable to the CaN group with an absence of resorption cavities, and more medullary bone filled the marrow cavity compared with the CaL group.

4. The CaL hens had significantly lower trabecular bone area, trabecular perimeter, per cent trabecular area, trabecular number and trabecular thickness and significantly wider trabecular separation compared with CaN. These results indicated that the low-calcium diet led to increased loss of tibial bone, eventually causing osteoporosis. However, compared with the CaL group, the IP2 group caused a significant increase in trabecular bone area and bone quality.

5. It is concluded that even in hens fed on a low-calcium diet, the addition of 20 mg/kg IP exerted beneficial effects on histological structure and structural histomorphometric parameters of tibia, indicating an alleviation of caged layer osteoporosis (CLO).     

Welfare of layers housed in small furnished cages on Danish commercial farms: the condition of keel bone,feet, plumage and skin

1. An on-farm assessment of keel bone, feet, plumage and skin damage was conducted in layers in small furnished cages to evaluate welfare implications.

2. Thirteen farms participated, all housing Lohmann LSL layers in systems allowing 8 or 10 hens per cage.

3. Each flock was visited at three different ages: 32, 62 and 77 weeks. During each visit, 100 hens were examined for keel bone fractures and deviations, plumage damage, body wounds, foot pad lesions, bumble feet, missing toes and toe wounds.

4. A deterioration with age of the condition of the plumage and keel bone was found (P < 0.001). At 77 weeks of age, 16% of the birds had poor plumage, and 43% of the birds had keel bone damage. In contrast, foot pad lesions were most prevalent at 32 weeks of age (13%), whereas the other foot injuries and body wounds remained at a relatively low level throughout the three ages examined.

5. Prevention of damage to the keel bone, plumage and foot pads should therefore be considered when aiming to improve welfare of laying hens housed in small furnished cages.     

Lycopene reduces the negative effects induced by lipopolysaccharide in breeding hens

1. This study assessed the effects of lycopene on the antioxidant capacity, biochemical parameters, and immune organ index of breeding hens following lipopolysaccharide (LPS) injection.

2. The study had a 2 × 2 factorial design. Healthy Xing-hua breeding hens (720) were divided into groups with 6 replicates per group and 30 hens per replicate. Hens were fed on a rice-soya bean basal meal supplemented with different levels of lycopene (0, 20, 40, or 80 mg/kg diet). On d 35, two hens from each replicate were injected subcutaneously with 1 mg/kg body weight of either LPS or sterile saline (control group). Blood samples were collected at 0, 6, and 24 h post-injection. At 24 h post-injection, hens were sacrificed and the thymus, spleen, and bursa of Fabricius were removed.

3. The results revealed that LPS significantly decreased high density lipoprotein cholesterol (HDLC), triidothyronine (T3), reduced glutathione to oxidised glutathione ratio (GSH/GSSG), thymus and bursal indexes, and increased low density lipoprotein cholesterol (LDLC). Lycopene supplementation significantly increased HDLC, T3, GSH/GSSG, and immune organ index, and decreased total cholesterol, LDLC, and blood urea nitrogen (BUN). The interaction effects of lycopene and LPS were significant on BUN and T3.

4. Lycopene supplementation affected inflammatory immune response based on increased immune organ index of breeding hens by relieving the LPS-induced stress.     

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.