The impact of in ovo injection of l-arginine on hatchability,immune system and caecum microflora of broiler chickens

The present article was conducted to evaluate the effect of in ovo injection of arginine on hatchability, immune system and caecum microflora of broiler chickens. For this reason, 300 fertile eggs were used in a completely randomized design with three experimental treatments. The experimental groups included: 1%–0.5% l -arginine (100 eggs), 2%–1% l -arginine (100 eggs), 3- control [included both sham control (injection of distilled water; 50 eggs) and control (no injection; 50 eggs)], which were injected on d 14 of incubation. After hatching, chicks of each experimental group (0.5% l -arginine, 1% l -arginine, and control groups) were randomly divided into four equal groups (as replicates) and reared for 30 days. Weight and feeding of chickens were recorded. Next, blood samples of chickens were collected on day 30 to evaluate antibody titre. Also, chickens were slaughtered on 24 and 30 days of the experiment to evaluate immune system organs and caecum microflora. Based on the results, in ovo injection of l -arginine had no significant effect on hatchability, body weight, antibody titre, spleen, bursa of Fabricius and thymus weight (p > .05). On the other hand, treatments significantly affected feed intake and feed conversion ratio (p < .05). As a novel finding, in ovo injection of l -arginine increased caecal Lactobacillus (p < .01), while decreasing Coliform and Escherichia Coli bacteria (p < .01). However, treatments did not influence caecal Enterococcus (p > .05). The overall results indicated that in ovo injection of 0.5% l -arginine had a better improving effect on caecal microflora and then considered as a recommended level of the present experiment.     

鸡胚给养氨基酸对肉仔鸡孵化率和胚胎生长的影响

本试验将90枚孵化第18天的落盘肉仔鸡胚蛋随机分为3组,分别向羊膜腔注射0.5mL复合氨基酸溶液、0.5mL生理盐水和不注射(对照组),研究对孵化率和后期胚胎生长的影响。结果显示:各处理组间的孵化率和出壳体重无显著差异(P>0.05),但出壳重与第18天胚蛋重的比值有显著差异(P<0.05),注射氨基酸组比对照组增加2.3%。这些结果表明鸡胚给养氨基酸可有效增加肉鸡出壳重。     

Effects of in ovo feeding of L‐arginine on the development of digestive organs,intestinal function and post‐hatch performance of broiler embryos and hatchlings

This study was to investigate the effects of in ovo feeding (IOF) L‐arginine (Arg) solution on the development of digestive organs, the duodenal mucosa of broiler embryos and hatchlings, and the growth performance of chicks during the first week post‐hatch. A total of 720 fertilized eggs with similar weight were randomly allocated to three groups, consisting of eight replicates of 30 eggs each. Three treatments were arranged as non‐injected control, diluent‐injected (0.75% NaCl solution) group and Arg solution‐injected group containing 1% Arg, dissolved in diluent. At 17.5 days of incubation, 0.6 ml of IOF solution was injected into amniotic fluid of each egg of injected groups. Results showed IOF of Arg solution increased (p < .05) the chick embryo weight at 19 days of incubation; the body weight gain of post‐hatch broilers during 1–7 days; the weights of liver, pancreas, proventriculus and gizzard; the concentrations of duodenal ghrelin, vasoactive intestinal peptide and glucagon‐like peptide 2; and the duodenum mucosal enzyme activities of alkaline phosphatase, maltase, sucrase and inducible nitric oxide synthase of 7‐day‐old post‐hatch broilers compared with other groups. The IOF of Arg solution also increased (p < .05) the villus height (VH) and the ratio of VH to crypt depth (CD) and decreased (p < .05) the CD in duodenum of broiler embryos and post‐hatch hatchlings, except for the CD at 19 days of incubation. In conclusion, IOF of 1% Arg solution into the amnion at 17.5 days of incubation could improve the development of digestive organs, the duodenal morphology, the releasing of gastrointestinal hormones and mucosal enzyme activities of broiler embryos and hatchlings and finally the growth performance of chicks during the first week post‐hatch. Therefore, IOF of appropriate Arg solution could be an effective technology for regulating early nutrition supply and subsequent growth development in poultry industry.     

Response of in ovo administration of zinc on egg hatchability and immune response of commercial broiler chicken

An experiment was conducted to determine the effect of in ovo administration of different forms of zinc with respect to hatchability and performance of commercial broiler chicken. In trial 1, the fertile eggs on day 18 were divided into six treatment groups: Group I as control without any supplementation of zinc, group II to IV were supplemented with 0.5 mg zinc per egg as zinc sulphate, zinc methionine or nano zinc, respectively, and Group V with nano zinc at 0.25 mg zinc per egg. Sixth group received 0.5 ml citric acid per egg as sham control. The results of the first trial indicated that in ovo administration of nano zinc at both levels and zinc methionine resulted in complete failure of hatchability. A second trial to validate the result of trial 1 consisted of Group I control (no administration). Group II and Group III were supplemented with zinc sulphate and zinc methionine, respectively, at 0.5 mg zinc per egg. Group IV and Group V were supplemented with nano zinc at 0.04 and 0.08 mg per egg. In the second trial, again there was a similar pattern for zinc sulphate and zinc methionine. Administration of Zn by nano form had around 80% hatchability on fertile eggs in comparison with the unadministered control eggs (92%). There was no difference (p > .05) in body weight gain, feed intake and FCR. No difference (p > .05) was observed between treatments for cell‐mediated immune response and humoral immune response. Nano Zn‐administered group showed a non‐significant downregulation of MUC2 gene. It could be concluded that in ovo administration of higher levels of zinc has to be with caution for the developing embryo of commercial broiler chicken.     

In ovo carbohydrate supplementation modulates growth and immunity‐related genes in broiler chickens

A study was undertaken to investigate the role of in ovo administrated carbohydrates on the expression pattern of growth and immune‐related genes. In ovo injections (n = 400) were carried out on the 14th day of incubation into the yolk sac/amnion of the broiler chicken embryos. Expression of growth‐related genes: chicken growth hormone (cGH), insulin‐like growth factor‐I & II (IGF‐I & II) and mucin were studied in hepatic and jejunum tissues of late‐term embryo and early post‐hatch chicks. Expression of candidate immune genes: Interleukin‐2, 6, 10 and 12 (IL‐2, IL‐6, IL‐10 and IL‐12), Tumour necrosis factor‐alpha (TNF‐α) and Interferon gamma (IFN‐γ) were studied in peripheral blood monocyte cells of in ovo‐injected and control birds following antigenic stimulation with sheep RBC (SRBC) or mitogen concanavalin A (Con‐A). Glucose injection significantly increased the expression of IGF‐II gene during embryonic period and both cGH and IGF‐II in early post‐hatch period, while ribose‐injected chicks had higher expression of IGF‐II gene during embryonic stage. Enhanced mucin gene expression was also observed in fructose‐injected chicks during embryonic age. Glucose‐injected chicks had higher expression of IL‐6 or IL‐10, while those injected with fructose or ribose had higher expression of IL‐2, IL‐12 and IFN gamma. It is concluded that in ovo supplementation of carbohydrates might help in improving the growth of late‐term embryos and chicks. In ovo glucose could modulate humoral‐related immunity, while fructose or ribose might help in improving the cellular immunity in broiler chickens.     

Effects of intra‐yolk‐sac injection of dextrose and albumin on performance,jejunum morphology,liver and pectoral muscle glycogen and some serum metabolites of broilers

This study carried out to investigate the effects of intra‐yolk‐sac injection (IYSI) of some solutions including 1 ml of distilled water, dextrose 20% and albumin 20% on hatch percentage, performance traits, jejunum morphology, glycogen content of liver and breast and serum metabolites in broilers (Ross 308). Fertile eggs were injected into the yolk sac at day 8 of incubation period. Results showed that hatchability, absolute body weight (BW), feed intake (FI) and feed conversion ratio (FCR) at day 7 and 14 of growing period were not different among treatments, but in comparison with control group, BW and FCR were numerally better by IYSI of albumin. In addition, IYSI of albumin increased jejunum villus height at hatch day, but crypt depth was not affected by any injection treatments. Also, the glycogen concentrations of liver and pectoral muscle in albumin injected group were significantly higher than control at hatch and 7th day respectively. At hatch day, serum glucose and cholesterol concentrations were, respectively, maximum and minimum statistically by IYSI of albumin which continued numerally up to 7th day of rearing period. Furthermore, liver glycogen and serum glucose concentrations were directly correlated on the day of hatch. In conclusion, the IYSI of albumin could increase performance traits, jejunum villus height, liver and breast glycogen and serum glucose in broiler chicks.     

Influence of in ovo inoculation with various nutrients and egg size on broiler performance

This study evaluated the influence of inoculation of different nutrients into eggs of 18-d-old broiler embryos. On d 18 of incubation, before transferring, eggs were injected with a solution containing either maltose, a multivitamin supplement, zinc-glycine, glutamine, a mixture containing all these elements, or sodium chloride (control). After hatching, 2,400 male broiler chicks were placed in an experimental broiler house and distributed into 60 floor pens in a completely randomized design comprising a 2 × 6 factorial arrangement of treatments (2 egg weights × 6 solutions), for a total of 12 treatments. Birds and feed consumption were measured weekly. At 42 d of age, 3 birds per replicate pen were randomly selected for processing. Birds derived from heavier eggs had greater hatchability and hatching weight. At 42 d of age, birds from heavier eggs had higher BW, carcass weight, and breast meat weight. The livability of birds derived from heavy eggs was higher at 7 and 14 d of age. The in ovo inoculation of the nutrients to 18-d-old embryos did not influence live performance or carcass traits. The technique of in ovo inoculation of certain nutrients may be used in industrial poultry production, but further studies are required to define the best solutions or mixture of nutrients to be used.     

The effect of n‐6/n‐3 fatty acid ratios on broiler breeder performance,hatchability, fatty acid profile and reproduction

This experiment was conducted to study the effect of dietary omega6 (n‐6) to omega3 (n‐3) fatty acid (FA) ratios on performance and reproduction of broiler breeders. In experiment 1, 400 females and 40 males (30 week age) of Ross 308 broiler breeder (20 females and two males in each pen) were randomly assigned to one of the four diets with n‐6/n‐3 FA ratios of 4, 6, 8 and 16 (control). As a measure of hatchability, fertility of eggs and general incubation traits, 1,200 eggs (60 eggs from each pen) were collected and incubated for 21 days and embryo liver and brain fatty acid profile in 14 and 21 days were determined. In experiment 2, 48 males (three males in each pen) randomly assigned to one of the four diets with n‐6/n‐3 FA ratios of 4, 6, 8 and 16 (control). Semen was collected twice weekly, and semen volume, spermatozoa concentration and motility and alive and dead spermatozoa were estimated. Egg production and egg mass were decreased by n‐6/n‐3 FA ratios of 4:1 and 6:1 (p < .05). There were no significant differences between treatments on breeder's body weight, eggs fertility and hatchability, embryonic mortality and semen features. Linolenic acid, eicosapentaenoic acid, docosahexaenoic acid and total n‐3 of egg yolk, semen, testis and liver and brain of embryo and day‐old chicken were increased while concentration of linoleic acid, arachidonic acid and docosatetraenoic acid of mentioned tissues were decreased by increasing n‐6/n‐3 FA ratios (p > .05). In conclusion, absolute amount of n‐3 and n‐6 FAs in broiler breeder diet may be more important than n‐6/n‐3 FA ratios and to consider reproductive and performance traits of breeders, it is necessary to supply higher levels of n‐3 and n‐6 FA with respect to n‐6/n‐3 FA ratios.     

Ileal MUC2 gene expression and microbial population,but not growth performance and immune response,are influenced by in ovo injection of probiotics in broiler chickens

1. The objective of present study was to evaluate the effects of intra-amniotic injection of different probiotic strains (Bacillus subtilis, Enterococcus faecium and Pediococcus acidilactici) on the intestinal MUC2 gene expression, microbial population, growth performance and immune response in broiler chicken.

2. In a completely randomised design, different probiotic strains were injected into the amniotic fluid of the 480 live embryos (d 18 of incubation), with 4 treatments and 5 replicates. Ileal MUC2 gene expression, microbial profile, growth performance and immune response were determined.

3. Injection of probiotic strains, especially B. subtilis, had significant effect on expression of the MUC2 on d 21 of incubation and d 3 post-hatch, but not on d 19 of incubation.

4. Injection of the probiotic strains decreased significantly the Escherichia coli population and increased the lactic acid bacteria population during the first week post-hatch.

5. Inoculation of probiotics had no significant effect on antibody titres against Newcastle disease virus, antibody titres against sheep red blood cell and cell-mediated immune response of chickens compared to control.

6. In ovo injection of the probiotic strains had no significant effect on growth performance of broiler chickens.

7. It was concluded that injection of probiotic bacteria especially B. subtilis into the amniotic fluid has a beneficial effect on ileal MUC2 gene expression and bacteria population during the first week post-hatch, but has no effect on growth performance and immune response in broiler chickens.     

In ovo leptin administration accelerates post‐hatch muscle growth and changes myofibre characteristics,gene expression and enzymes activity in broiler chickens

To evaluate the effect of maternal leptin on muscle growth, we injected 0 μg (control, CON), 0.5 μg (low leptin dose, LL) or 5.0 μg (high leptin dose, HL) of recombinant murine leptin dissolved in 100 μl of PBS into the albumen of broiler eggs prior to incubation. The newly hatched chicks were all raised under the same conditions until 21 days of age (D21), when body weight was measured and samples of gastrocnemius muscle were collected and weighed. Myosin ATPase staining was applied to identify myofibre types and measure the cross‐sectional area (CSA) of myofibres. Real‐time PCR was performed to quantify leptin receptor (LEPR), insulin‐like growth factor 1 (IGF‐1), IGF‐1 receptor (IGF‐1R), growth hormone receptor (GHR) and myostatin (MSTN) mRNA expression in the gastrocnemius muscle. The activity of calpains (CAPNs) in the gastrocnemius muscle was measured using a quantitative fluorescence detection kit. Male chickens treated with both high and low doses of leptin had significantly higher (p < 0.05) body weight on D21. The high leptin significantly increased the CSA (p < 0.05) of gastrocnemius muscle in male chickens, which coincided with a 93% increase (p < 0.05) in IGF‐1 mRNA expression. Likewise, the LL dose increased the weight of gastrocnemius muscle in male chickens (p < 0.05), which was accompanied by a 41% down‐regulation (p < 0.05) of MSTN mRNA expression and a decreased activity of CAPNs. However, all these changes were not observed in female chickens. The proportion of myofibre types did not altered. No significant change was detected for LEPR and GHR mRNA expression. These results indicate that in ovo leptin treatment affects skeletal muscle growth in chickens in a dose‐dependent and sex‐specific manner. The altered expression of IGF‐1, MSTN mRNA and activity of CAPNs in skeletal muscle may be responsible for such effects.     

The effect of maternal vitamin D source on broiler hatching egg quality,hatchability, and progeny bone mineral density and performance

Vitamin D is involved in calcium metabolism as well as bone and shell quality, and is therefore important to broiler breeders. In this research we investigated the effects of maternal dietary 25-OH vitamin D₃ on broiler breeder egg quality and hatchability, as well as on progeny bone mineral density and performance. In a field study, all hens were fed 3,000 IU of vitamin D₃ (D) per kilogram of complete feed; in addition half of the hens also received 34.5 µg of 25-OH vitamin D₃ per liter in the drinking water (25OHD). Eggs from each treatment group were incubated and hatched; chicks were fed a common diet and grown to 41 d of age. Eggs from hens in the 25OHD treatment had a nearly 30% reduction in early embryo mortality. However, a larger egg size resulted in greater chick BW for the D chicks, although this did not affect broiler production performance. Broilers from the maternal 25OHD treatment had a lower FCR during the grower phase. Unexpectedly, chick plasma 25-OH vitamin D₃ was only greater for the maternal 25OHD treatment at 4 d of age, but not at hatch, 2, 6, 8, 10, 12, or 14 d of age. Maternal vitamin D₃ source did not affect progeny 41-d bone mineral density. Maternal 25-OH vitamin D₃ had a protective effect on the growing embryo, reducing early embryonic mortality, with minimal effects on progeny performance and bone mineral density to processing at 41 d of age. The previously reported effects of 25-OH vitamin D₃ on increasing broiler performance and breast yield seem to be dependent on supplementation of the broiler diet; a carry-over effect of maternal supplementation is insufficient to achieve these effects.     

Effect of arginine and threonine administered in ovo on digestive organ developments and subsequent growth performance of broiler chickens

This trial was conducted to investigate the effect of arginine (Arg), threonine (Thr) and Arg + Thr administered in ovo on growth performance, digestive organs and intestinal morphology in broiler chickens. On day 14 of incubation, 400 fertile eggs were randomly allotted to five experimental treatments through injection in the amniotic fluid including: (i) control (none injected), (ii) sham (0.5 ml of 0.5% saline), (iii) Arg (35 mg/egg), (iv) Thr (25 mg/egg) and (v) Arg + Thr (35 + 25 mg/egg). After hatching, chicks were given a commercial corn–soya bean diet up to 42 days of age. Daily feed intake (FI) and body weight (BW) of chicks were measured during different periods of the trial. Digestive organs were measured for their relative weight and intestinal length on days 11 and 42 of age. Intestinal morphometric traits were evaluated on day 11 of the experiment. Supplementing amino acids affected the performance of broiler chicks as Thr significantly increased FI and BW across starter, grower and finisher periods compared with sham and control (p < 0.05). Furthermore, Arg + Thr injection increased jejunal weight compared with control on day 42 (p < 0.05). Moreover, Arg inclusion led to the greatest villus height and crypt depth among treatments in duodenum (p > 0.05); however, amino acid supplemented groups had lower villus height than control in jejunum (p < 0.05). Negative correlations found between digestive organs related to day 11 of age containing pancreas (r = ?0.484; p = 0.030), duodenal (r = ?0.577; p = 0.007) as well as ileal lengths (r = ?0.471; p = 0.035) and FI of entire period. Otherwise, positive relationships were observed between duodenum (r = 0.580; p = 0.007) and ileum (r = 0.582; p = 0.007) weights on day 42 and FI of chickens across the entire phase. In conclusion, Arg and particularly Thr injection into amnion can improve FI and post‐hatch growth performance of chickens which may be mediated by the development of digestive organs.     

Effect of in ovo glyphosate injection on embryonic development,serum biochemistry,antioxidant status and histopathological changes in newly hatched chicks

This study aimed to investigate the potential toxic effects of pure glyphosate or Roundup^® on hatchability, serum biochemistry and histopathological observation of the liver and kidney of newly hatched chicks. On day six, a total of 225 fertile eggs were obtained from Huafeng breeder hens. The eggs were randomly divided into three treatments: (a) the control group injected with deionized water, (b) the glyphosate group injected 10 mg pure glyphosate/Kg egg mass and (c) the Roundup group injected 10 mg the active ingredient glyphosate in Roundup^®/Kg egg. The results showed a decrease of hatchability rate in chicks treated with Roundup^® (66%). In addition, no significant change was observed in body weights, yolk sac weight and relative weight organs except the liver and kidney were significantly increased with groups treated with glyphosate and Roundup^® compared to the control group. The results showed that serum protein profiles were linearly significantly increased of serum phosphor, uric acid, aspirate aminotransferase, alanine transaminase and alkaline phosphatase in groups treated with Roundup^®, as well as the serum concentrations of triglyceride altered after treatment with glyphosate. Furthermore, oxidative stress was observed in the treated chicks, the glyphosate and Roundup^® induced changes of the content of malondialdehyde in both the liver and kidney, moreover decrease of glutathione peroxidase, total superoxide dismutase and catalase activity in the kidney tissue and serum. Additionally, changes also happened in the histomorphology of the liver and kidney tissue of the treated chicks. It can be concluded that Roundup^® as a probable decrease of hatchability. Exposure to glyphosate alone or Roundup^® caused liver and kidney histopathological alterations, serum parameters imbalances and oxidative stress, also induced a variety of liver and kidney biochemical alterations that might impair normal organ functioning in newly hatched chicks.     

In ovo injection of branched‐chain amino acids: Embryonic development,hatchability and hatching quality of turkey poults

In this study, the influence of a branched‐chain amino acid blend (BCAA composed of 3 l ‐leucine:1 l ‐valine:2 l ‐isoleucine) injected into the amniotic fluid was evaluated for embryonic growth, yolk‐sac (YS) utilization and development of gastrointestinal tract (GIT) and skeletal muscles of turkey embryos from day 24 of incubation (24E) to hatching, together with hatchability, poult quality and liver L* (lightness), a* (redness) and b* (yellowness) values at hatch. At day 22 of incubation, embryonated eggs (n = 240) were assigned to three treatments, that is, eggs were not injected (control, NC) or injected with 1.5 ml sterile solution with 0.9% salt (SA) or 0.2% BCAA blend (BCAAb). These solutions were injected manually into the amniotic fluid of the embryonated eggs. To determine weights and lengths (where appropriate) of the studied organs and tissues, four embryonated eggs and poults per treatment were selected at 24E and at hatch. While the BCAAb decreased the YS and embryo weight, hatchability and the liver L* value, it increased the weight and quality of poults and the weights of breast and thigh muscles at hatch. In conclusion, the in ovo feeding of the BCAA blend negatively affected hatchability but positively affected hatching weight and poult quality by improving development of skeletal muscles and by regulating energy metabolism.     

In ovo injection of flavanone on bone quality characteristics,biochemical parameters and antioxidant enzyme status of blood in daily chicks

In ovo injection (IOI) of Naringin (N), flavanone was examined on post‐hatch blood biochemical parameters, antioxidant status and bone characteristics. Fertile eggs (n = 700) were distributed in seven groups with 100 eggs. On 14th and 17.5th days of incubation, four groups were injected using 15 or 30 mg active ingredient levels of naringin/0.5 ml saline/egg, low and high level, into amnion sac. Controls include sham (injected normal saline, 0.5 ml/egg on day 14 and 17.5th) and un‐injected group. IOI of high naringin and saline on 14th day of incubation resulted in lower hatchability and then higher mortality in last week of embryonic life. On day hatch, high levels of injected groups more body weight compared to the control. Chick length was increased at high levels of naringin on day 17.5th compared to control and saline injected. Quality traits of bones were improved in naringin‐injected groups compared to control. IOI of naringin influenced thyroid hormones on 14th day of incubation. Naringin groups influenced the Alkaline phosphatase (ALP), Calcium (Ca), superoxide dismutase (SOD), blood biochemical and lipids. Totally, amniotic IOI of naringin in last days of developing embryo may be useful for hatched chick, development of leg long bone or effect on biochemical metabolites by levels of flavanone that it needs more research.     

Effect of adjuvants on in ovo vaccination against Newcastle disease on hatchability,performance and antibody titres in commercial pullets

This study was conducted to investigate the efficacy of in ovo administration of aluminium hydroxide (AH) and/or mannan oligosaccharide (MOS) adjuvants along with lentogenic VG/GA strain‐Avinew to alleviate the embryonic pathogenicity of Newcastle disease virus. Six hundred and thirty fertilized Bovans eggs were divided into nine groups of 70 each incubated in a commercial hatchery and administered with eight types of in ovo injections in a factorial design of 2 × 2 × 2 including with/without AH, MOS and Newcastle disease vaccine (NDV), and one uninjected group on day 18 of incubation. Hatchability was higher in the eggs received MOS and/or AH adjuvants plus NDV compared those injected with NDV alone which confirmed the attenuation of NDV. However, the average daily feed intake and feed conversion ratio of pullets hatched from NDV‐injected eggs were significantly reduced, but did not affect growth performance during 0‐42 days of age. The performance of pullets hatched from eggs injected with AH, MOS or their mixture with NDV was not significantly different during all growth periods. Pullets from MOS + vaccine injected eggs had significantly higher antibody titres against NDV compared to those hatched from either injected with saline or uninjected on d 28 (p < .05). In addition, AH plus vaccine and MOS significantly improved total anti‐SRBC and IgG respectively. Histological observation revealed that injection of MOS adjuvant into eggs led to increase crypt depth, whereas AH injection caused a reduction in villus surface area of jejunum in chicks on d 14 post‐hatch. It is concluded that in ovo MOS injection as compared to AH may be more effective to attenuate the embryonic pathogenicity of in ovo NDV injection.     

Effects of in ovo administration of L-carnitine on hatchability performance,glycogen status and insulin-like growth factor-1 of broiler chickens

1.?Eggs from a meat-type breeder flock (Ross) were used in two trials to study the effects of in ovo administration of L-carnitine (carnitine) on hatchability traits (hatchability percentage, embryo deaths, pipped with live or dead embryo), chick weight at hatch as an absolute value (CWT) or expressed as a percentage of egg weight (CWT%), hatching period, glycogen status (liver and pectoral muscle) and plasma insulin-like growth factor-1 (IGF-1) of hatched chicks were investigated. There were 9 treatments with three replicates of each. Treatments were non-injected control (negative control), or injection with sterilised saline (0?9%, positive control), or sterilised saline with carnitine at 25, 50, 100, 200, 300, 400, and 500 µg/egg.

2.?In ovo carnitine treatment increased CWT, CWT%, glycogen in the liver and pectoral muscle, glycogen index and plasma IGF-1 of hatched chicks, and did not influence hatchability traits and hatching period. The glycogen index of hatched chicks of the in ovo carnitine treatments with values (500 > 400 = 300 > 200) was higher than that of the control and in ovo carnitine at 25, 50, and 100 µg/egg treatments. The nature of response to carnitine was cubic for CWT and CWT%, and linear for glycogen in the liver and pectoral muscle, glycogen index of hatched chicks when the negative control or positive control treatment was used as base line.

3.?It was concluded that in ovo administration of carnitine at 25–500 µg/egg increased chick weight at hatch and IGF-1, and did not influence hatchability traits and hatching period of eggs. The linear relationship between in ovo administration of carnitine and glycogen status of hatched chicks indicated that increasing in ovo doses improved glycogen status of hatched chicks.     

Effect of dosage and application mode of l‐carnitine on plasma lipid and egg‐yolk cholesterol of turkeys,hatchability of eggs and post‐hatch growth of their offsprings

The effect of dosage and application mode of l ‐carnitine on plasma lipid and egg‐yolk cholesterol of breeder turkeys, hatchability of eggs and post‐hatch growth response was investigated using 180 breeder hens. The hens were assigned to six dietary treatments in a 2 × 3 factorial arrangements of two application modes of l ‐carnitine (diet and drinking water) supplemented at 0, 50 and 100 ppm (mg/kg or mg/l) levels, respectively. Each treatment was replicated five times with six hens per replicate. Dietary inclusion of 50 ppm l ‐carnitine showed the lowest (p < 0.01) plasma total cholesterol (TC) and low‐density lipoprotein concentration (LDL). Breeder hens offered 50 ppm l ‐carnitine with no regard to application mode recorded the highest (p < 0.01) plasma high‐density lipoprotein (HDL). Hens offered 50 and 100 ppm l ‐carnitine irrespective of application mode also showed reduced (p < 0.01) egg‐yolk TC concentration at 32 weeks of age. Dietary supplementation of 50 ppm l ‐carnitine for breeder turkeys recorded the lowest (p < 0.01) egg‐yolk triglyceride (TG) at 40 weeks of age. Hens offered 50 ppm l ‐carnitine irrespective of application mode recorded the highest (p < 0.05) hen‐day egg production. Incidence of dead‐in‐shell also reduced (p < 0.05) with increasing dosage of l ‐carnitine. Dietary supplementation of 50 ppm and oral application in drinking water of 100 ppm l ‐carnitine for breeder turkeys resulted in highest (p < 0.05) egg fertility. Offsprings from breeder hens fed diets supplemented with l ‐carnitine recorded no post‐hatch mortality. Highest (p < 0.05) post‐hatch final live weight and weight gain was obtained with poults obtained from hens fed diet supplemented with 50 ppm l ‐carnitine. In conclusion, dietary supplementation of 50 ppm l ‐carnitine for turkey hens showed improved serum lipid profile, egg fertility, reduced dead‐in‐shell, egg‐yolk cholesterol and resulted in improved post‐hatch growth performance.     

Effects of dietary inclusion of silymarin on performance,intestinal morphology and ileal bacterial count in aflatoxin‐challenged broiler chicks

This study was conducted to investigate the effect of dietary supplementation of silymarin on performance, jejunal morphology and ileal bacterial population in broiler chicks intoxicated with a mix of aflatoxins. A total of three hundred thirty six 7‐day‐old Ross broiler chicks were randomly distributed between seven experimental groups with four replicates of 12 birds each. Experimental treatments consisted of a control group (unchallenged), and a 2 × 3 factorial arrangement, including two aflatoxin levels (0.5 and 2 ppm) and three levels of silymarin (0, 500 and 1000 ppm). Birds were challenged with a mix of aflatoxins from 7 to 28 days of age. Results showed that increasing aflatoxin level resulted in decreased average daily feed intake (ADFI) and weight gain (ADWG), consequently impaired feed conversion ratio (FCR) throughout the trial period. Dietary supplementation of silymarin resulted in the marked increases in ADFI and ADWG, and improved FCR values in aflatoxin‐challenged chicks. Ileal bacterial populations at days 28 and 42 of age were increased by incremental levels of aflatoxins. On the other hand, dietary silymarin supplementation suppressed ileal populations of Escherichia coli, Salmonella, Klebsiella and total negative bacteria in aflatoxicated birds. Increase in dietary aflatoxin level resulted in the decreased villi height, villi height‐to‐crypt depth ratio (VH:CD), villi surface area and apparent villi absorptive area, while it increased crypt depth, goblet cell count and lymphoid follicular diameter. Feeding silymarin at the level of 1000 ppm increased villi height and VH:CD in aflatoxicated birds. Present results indicate that dietary inclusion of silymarin could improve performance by suppressing ileal bacteria and enhancing absorptive surface area in aflatoxin‐challenged broiler chicks.