Attenuation by leptin of the effects of fasting on ovarian function in hens (Gallus domesticus)

Thirty-four-week-old laying hens received injections of recombinant chicken leptin to assess the role of leptin in avian ovarian function. In the first experiment, the hens (n=60) were divided into three groups: (i). fed ad libitum; (ii). fasted; and (iii). fasted + leptin. Hens were fasted for 5 days and those treated with leptin received 250 microg leptin kg-1 body weight twice a day, i.p. In the second experiment, the hens (n=72) were divided into four groups: (i). fed ad libitum; (ii). fasted; (iii). fasted + leptin given only during fasting (5 days); or (iv). fasted and leptin given during both fasting and 5 days of re-feeding (10 days). LH was measured in blood plasma, and progesterone and oestradiol were measured in blood plasma and the ovary by radioimmunoassay. Apoptosis was examined in the walls of the three largest yellow hierarchical follicles (F3-F1; F3 25-35 mm) by the TdT-mediated dUTP nick-end labelling method. Results showed that the injections of leptin during fasting: (i). delayed cessation of egg laying; (ii). attenuated regression of yellow hierarchical follicles; (iii). altered ovarian steroidogenesis; and (iv). abolished the fasting-induced apoptosis in the wall of F3-F1 follicles during the first 2 days of fasting and partially attenuated apoptosis after 5 days of fasting. Prolongation of leptin injections into the re-feeding period considerably delayed the restoration of the ovary. Expression of leptin receptor in laying hens was determined by RT-PCR. The highest expression of leptin receptor was observed in the hypothalamus. Lower receptor mRNA expression was found in the hypophysis, whereas the lowest expression was observed in the ovary. Within the ovary, a relatively high expression of leptin receptor was found in the stroma with cortical follicles <1 mm, the wall of white (1-8 mm) and small yellow follicles (>8-12 mm), and the granulosa layer of F3 follicles. The expression of leptin receptor in the granulosa layer of F2 and F1 follicles was barely detectable. This was in contrast to a much higher expression of leptin receptor maintained in the theca layer of F3-F1 follicles. The present results indicate that in chickens leptin might be involved in the adaptation to starvation due to attenuation of follicular apoptosis. The presence of leptin receptors in the ovary indicates the possibility of a peripheral effect of the hormone.

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Identifications of radioactive steroid estrogen conjugates in blood plasma of laying hens after intramuscular injection of [4-14C]-es tr one

Steroids ◽

10.1016/0039-128x(75)90022-7 ◽

1975 ◽

Vol 25 (5) ◽

pp. 677-695 ◽

Cited By ~ 1

Author(s):

A.H-H. Chan ◽

A.R. Robinson ◽

R.H. Common

Keyword(s):

Blood Plasma ◽

Intramuscular Injection ◽

Laying Hens ◽

Steroid Estrogen ◽

In Blood Plasma

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Effects of Genotype, Age and Their Interaction on Egg Quality in Brown-Egg Laying Hens

Acta Veterinaria Brno ◽

10.2754/avb200978010085 ◽

2009 ◽

Vol 78 (1) ◽

pp. 85-91 ◽

Cited By ~ 44

Author(s):

Lukáš Zita ◽

Eva Tůmová ◽

Ladislav Štolc

Keyword(s):

Laying Hens ◽

Egg Quality ◽

Quality Characteristics ◽

Egg Laying ◽

Eggshell Thickness ◽

Egg Weight ◽

Eggshell Quality ◽

Ad Libitum ◽

Quality Measurements

The experiment compared the effects of strain and age on egg quality characteristics in ISA Brown, Hisex Brown and Moravia BSL brown-egg laying hens. One hundred and eight ISA Brown hens, forty-five Hisex Brown and forty-five Moravia BSL 20 to 60 weeks old were housed in conventional cages (550 cm2 per hen). Feed and water were available ad libitum. Eggs were sampled at 21-day intervals, every collecting week 150 eggs per genotype in three age periods, from 20 to 26 weeks, 37 to 43 weeks and 54 to 60 weeks of age. A total of 4,050 eggs were examined. Egg quality characteristics were affected by genotype and age. Egg weight, yolk weight and percentage, Haugh Units increased with the hens’ age in all genotypes, but albumen and eggshell percentage decreased, eggshell thickness and strength improved with age. The highest egg weight (65.3 g) and yolk quality (yolk index 45.1%) were found in Moravia BSL at the end of the experiment. In contrast, the best albumen quality (albumen percentage 60.0) values were in Hisex Brown and the eggshell quality measurements (eggshell thickness 0.38 mm) were higher in ISA Brown.

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Interrelationships between Diet and Elevated Temperatures (Cyclic and Constant) on Concentrations of Progesterone, Estradiol-17β, and Testosterone in Blood Plasma of Laying Hens

Poultry Science ◽

10.3382/ps.0571042 ◽

1978 ◽

Vol 57 (4) ◽

pp. 1042-1051 ◽

Cited By ~ 4

Author(s):

R.E. ERB ◽

A.N. de ANDRADE ◽

J.C. ROGLER

Keyword(s):

Blood Plasma ◽

Elevated Temperatures ◽

Laying Hens ◽

Estradiol 17Β ◽

In Blood Plasma

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Comparison of Sex Steroid Concentration in Blood Plasma and Ovarian Follicles of White Leghorn and Greenleg Partridge Laying Hens

Annals of Animal Science ◽

10.2478/v10220-011-0003-1 ◽

2011 ◽

Vol 11 (4) ◽

pp. 507-520 ◽

Cited By ~ 2

Author(s):

Andrzej Sechman ◽

Mirosława Staruszczak ◽

Janusz Rząsa

Keyword(s):

Blood Plasma ◽

Laying Hens ◽

Average Rate ◽

Ovarian Follicles ◽

Sex Steroid ◽

Blood Collection ◽

White Leghorn ◽

Laying Performance ◽

Reverse Relationship ◽

In Blood Plasma

Comparison of Sex Steroid Concentration in Blood Plasma and Ovarian Follicles of White Leghorn and Greenleg Partridge Laying HensThe study was performed to compare plasma and ovarian levels of progesterone (P4) and estradiol (E2) with laying rate in two different breeds of egg-type chickens, i.e. White Leghorn (WL) and Greenleg Partridge (GP). Thirty-five-week-old WL (line H22; n = 8) and GP (line Z11; n = 8) hens were used in the experiment. Blood samples were collected from hens at the time of C1 oviposition (i.e. 0.5 h before C2 ovulation), then at 20, 16, 12, 8, 4, 2 h before C3 ovulation, and at the time of predicted C3 ovulation (i.e. just after C2 oviposition). On the following day, six birds of each breed were decapitated 2 h before ovulation on the next day after the last blood collection. A stroma, small (SWF; 1-4 mm), medium (MWF; 4-6 mm) and large (LWF; 6-8 mm) white prehierarchical follicles, and yellow hierarchical (F6-F1; 8-36 mm) ovarian follicles were isolated. P4 and E2 levels in blood plasma and ovarian follicles were determined radioimmunologically. The average rate of lay in WL hens was significantly higher than in GP hens (P<0.05). The highest concentrations of P4 and E2 were found 4 h before ovulation in both WL and GP hens. In WL hens the levels of P4 at the time of oviposition and at 4 and 2 h before ovulation were significantly higher in comparison with GP hens (P<0.05). On the other hand, higher E2 concentrations were found in GP hens at the time of oviposition and 12, 8 and 4 h before ovulation (P<0.05). In LWF and hierarchical follicles of WL hens the level of P4 was significantly lower than in GP hens (P<0.05). With respect to E2, a reverse relationship was observed in LWF and F6-F4 follicles. In conclusion, the results obtained indicate that in egg-type layers the profiles of plasma and ovarian sex steroids depend on their genotype. The significant differences in sex steroid levels in blood and ovarian follicles of the WL and GP breeds may contribute to explain the endocrinological factors that determined their laying performance and productivity.

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Differences between metabolic profiles of egg-type and meat-type hybrid hens

Czech Journal of Animal Science ◽

10.17221/4316-cjas ◽

2011 ◽

Vol 49 (No. 8) ◽

pp. 323-328 ◽

Cited By ~ 3

Author(s):

P. Suchý ◽

E. Straková ◽

B. Jarka ◽

J. Thiemel ◽

V. Večerek

Keyword(s):

Blood Plasma ◽

Biochemical Parameters ◽

Metabolic Profile ◽

Egg Laying ◽

Haematocrit Level ◽

Production Type ◽

Significant Difference ◽

Biochemical Analyses ◽

Meat Type ◽

In Blood Plasma

The main objective of this study was to compare the metabolic profile (i.e. selected haematological and biochemical parameters in blood plasma) of production egg-type hybrid hens (E, MORAVIA BSL) with that of meat-type hybrid hens (M, COBB 500), and to evaluate dynamic changes occurring during the laying period from the 25th to 50th week of age. The study was prompted by both poultry farmers and veterinary practitioners since parameters defining the health of layers are absent. Selected parameters of the metabolic profile of layers were monitored regularly in 5-week intervals during egg laying. Samples of blood for haematological and biochemical examination were obtained by puncture of the vena basilica and stabilized by heparin. The study has revealed that monitored parameters of the metabolic profile significantly vary with factors such as production type, nutrition, and egg-laying intensity. Enhanced metabolism in egg-type hens was reflected in erythropoiesis which increased (in comparison with meat-type hens) highly significantly (P ≤ 0.01), particularly for erythrocyte count 2.36 T/l (2.14 T/l), haematocrit level 0.32 l/l (0.30 l/l), content of haemoglobin 94.48 g/l (84.18 g/l) and leukocyte count 17.06 G/l (13.22 G/l). Similarly, enhanced metabolism in egg-type hens also led to a highly significant increase (P ≤ 0.01) in the levels of biochemical parameters in blood plasma, particularly the total level of protein was 57.62 g/l (50.98) g/l), glucose 14.03 mmol/l (13.36 mmol/l), cholesterol 5.34 mmol/l (3.73 mmol/l) and calcium 6.52 mmol/l (5.52 mmol/l). ) In the case of the plasma level of phosphorus, no significant difference was found between egg-type hens (1.58 mmol/l) and meat-type hens (1.59 mmol/l). The reported results are based on the total of 180 haematological and biochemical analyses performed during the laying period. The results are crucial not only for future development of avian haematology and biochemistry, but also in respect to veterinary practice.    

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