The effect of the dietary electrolyte balance on the plasma energy, protein, mineral variables and endocrine profile of pluripare rabbit does

In this research, the effect of the electrolyte balance (dEB, dEB=Na+K-Cl) on the plasma energy, protein, enzyme, mineral profile and on the endocrine response of rabbit does was studied. The animals, belonging to the Grimaud genotype, were at the third reproductive cycle. The rabbits were allocated to reproductive cages and divided into two groups to be fed two diets with different electrolyte balances (dEB1=27 meq/100g and dEB2=35 meq/100g). The diets were similar in ingredients, protein (CP=19.81% d.m.) and energy content (DE=2945 kcal/kg d. m.), whereas they had different sodium content (dEB1=0.21% d.m. and dEB2=0.38% d. m.). The animals were fed the two diets from first mating (20 weeks of age) until the litter weaning of the third reproductive cycle. From the mating of the third cycle the environmental temperature averaged 15\ub0C and the relative humidity was about 79%. At about 39 weeks of age, five days after parturition, a blood sampling was performed on the does. Results pointed out that the two dEB levels did not significantly affect the body weight and feed intake of rabbit does. No significant dEB effect was observed on the main variables of plasma metabolic (glucose, triglycerides, cholesterol, total proteins, albumin and globulines), enzyme (aspartate-aminotransferase, alanine-aminotransferase, ?-glutamyl-transpeptidase), and mineral (Ca, P, K, Na, Cl) profile. The plasma concentration of 17 f-oestradiol was similar between the two groups. Cortisol plasma level slightly increased in dEB2 rabbits. Also the triiodothyronine (T3) and thyroxine (T4) were unaffected by the dietary dEB level as well as the free fractions (FT3 and FT4). The results point out that a prolonged administration of a diet with an electrolyte balance of 35 meq/100 g does not affect the metabolic and mineral profile nor the oestradiol plasma level but tendentially increases the thyroid hormones of pluripare lactating rabbit does when they are in neutral thermal conditions

A study on the reproductive performance and physiological response of rabbit bucks fed diets with two different mineral contents

The reproductive performance and the plasma biochemical profile of rabbit bucks relating to two dietary electrolyte balances (dEB, dEB=Na+K-Cl) were investigated. Two pelleted diets were fed the male rabbits from the first mating (50 weeks of age) until the weaning of the litters of the third reproductive cycle. The diets were similar in composition and were isoproteic (crude protein=19.81% d. m.) and isoenergetic (digestible energy=2945 kcal/kg d. m.); the sodium content was 0.21 an 0.38% d. m. and the electrolyte balance was 27 meq/100g and 35 meq/100 g in the dEB1 and dEB2 diets, respectively. The higher sodium level in the diet was obtained by increasing the mineral content in the supplement of the feed. Matings occurred with natural insemination. The trial started in the summer period under a hot climate but the third cycle presented neutral thermal hygrometric conditions (temperature=15\ub0C and relative humidity=79%). The photoperiod was 16L:8D. At the third cycle, at 70 weeks of age, the bucks were submitted to a blood sampling early in the morning. At the third reproductive cycle, the dEB2 diet did not significantly affect the body weight and the feed intake of the rabbits. The two experimental groups presented a similar number of kids born and born alive and number of kids/mating. Plasma glucose, triglycerides, cholesterol, total proteins, albumin and globulines resulted unaffected by the diets. The plasma enzyme activities (aspartate-aminotransferase, alanine-aminotransferase, \u3b3-glutamyltranspeptidase) and the mineral contents of calcium, phosphorus, potassium, sodium and chloride were similar between the groups. No significant difference was observed for plasma cortisol, even if the higher dEB level induced a tendential decrease in dEB1 group. T3 (thriiodothyronine), T4 (thyroxine) and FT3 (free T3) were similar between the groups. FT4 (freeT4) slightly increased in the dEB2 rabbits. Results indicate that using daily rations with an electrolyte balance ranging from 27 to 35 meq/100 g continuously for three reproductive cycles did not exert any effect on the reproductive performance of the bucks nor on the biochemical profile

Performance and behaviour of rabbit does in a group-housing system with natural mating or artificial insemination

This study compared reproductive performance and behaviour of does raised in a group-housing system and in a regular cage system. The group-housing pen was divided into different functional areas for suckling, resting, and eating and special hiding areas for kits when they had left the nest-boxes and does to favour the species specific behavioural traits. Does had access to their nest-box by means of an individual Electronic Nest-box Recognition System (ENRS) activated by a coded transponder placed in their eartags. Eight does were housed in each pen. Natural mating (NM, with a buck in the group) or artificial inseminations (AI) were applied. Litter size, kit mortality and kit weight at 14 d of age were similar for group-housing and cages when NM were applied. With a natural reproduction rhythm group-housing led to an increase of +38% of litters. However, from a management point of view, a cycled production system with AI is preferred. With AI and group-housing, a lower kindling rate and a lower kit weight at weaning were found. The lower kindling rate was partly caused by pseudo-pregnancies that were found in 23% (P < 0.01) of the does in the group-housing system against 0% in the control group. Sixteen to 20% of the does in the group-housing system had skin injuries, which is an indicator for aggression among does. Most of the injuries were seen on the body and most of them were superficial bites. Based on the results of this study, it can be concluded that group-housing of rabbit does seems possible, but more research is needed to solve the problems of the decreased kindling rate and occurrence of pseudo-pregnancies, the lower weight at weaning and aggressiveness among does

The physiological dilemma of the high progesterone syndrome in rabbit does

This work focused on the mechanisms that may cause multiple asynchronous ovulations and alter normal ovarian function in order to characterize the high progesterone (P+) syndrome in rabbit does, that, having abnormally high plasma progesterone concentration at the time of insemination, fail to become pregnant. At different luteal stages, at either days 4, 9, or 13 of pseudopregnancy, induced by GnRH injection (d-0), two groups of rabbits (n=5/group) were treated with saline or 0.8 \ub5g GnRH. Blood samples were collected from d-0 to d-26 of pseudopregnancy. At d-4, GnRH injection prolonged (P<0.05) the functional CL life span by 3 to 4 d over that of controls. At d-9, GnRH caused a transient decline (P<0.01) of progesterone for the following 3 d but, thereafter, increased again and remained higher (P<0.01) than controls up to d-26. At d-13, progesterone fell to 1 ng/ml within one day following GnRH, but then gradually increased. Based of these progesterone profiles, it can be argued that, at both mid- and late-luteal phase, GnRH triggered luteolysis and induced ovulation followed by the formation of a new generation of CL. For the in vitro study, CL, collected at days 4, 9, and 13 of pseudopregnancy, were incubated with GnRH, GnRH-antagonist, PLA2 inhibitor, and PLC inhibitor. GnRH decreased (P<0.01) progesterone secretion by d-9 and d-13 CL cultured in vitro; by converse, GnRH antagonist, increased (P<0.01) progesterone release from d-4 CL. Co-incubation of GnRH with GnRH antagonist increased (P<0.01) progesterone release in d-4 CL, but had an opposite effect (P<0.01) on d-9 and d-13 CL. PLC inhibitor reversed the GnRH effects in both d-9 and d-13 CL, while PLA2 inhibitor did not change progesterone release. These data suggest that rabbit CL express a functional receptor for GnRH, likely of type II, that utilizes the PLC post transductional cascade. Luteal FSH-R and LH-R mRNA relative abundances did not differ between d-4 and d-9 CL, but were two- to three-fold (P 640.01) higher, respectively, at d-13. StAR mRNA was highly expressed at d-4 of pseudopregnancy, but then markedly declined (P 640.01) at d-9 and d-13. Taken together, our results show that GnRH triggers i) functional regression when CL acquire luteolytic capacity from d 9 of pseudopregnancy onward, and ii) multiple asynchronous ovulations, thus partly explaining the P+ syndrome associated with the simultaneous coexistence of two population of \u201cfresh\u201d and \u201cold\u201d CL, although not yet the underlying causes

The different effects of linseed and fish oil supplemented diets on insulin sensitivity of rabbit does during pregnancy

This study investigates the effects of linseed (rich in ɑ-linolenic acid (ALA)) and fish oil (rich in eicosapentaenoic (EPA) and docosahexaenoic acid (DHA)) supplementation on the insulin resistance of pregnant rabbits. Two months before insemination, the rabbits (15 animals/group) were fed different diets: commercial standard (group C), supplemented with 10% extruded linseed (group L), and 3% fish oil (group FO). The L group does showed both the highest feed intake before AI (P < 0.01) and the highest body weight (BW) throughout pregnancy (P < 0.001). The L does yielded less milk than the C does (P < 0.001); however, no differences were observed in either weight or size of litter at weaning. Regardless of diet, insulin concentrations and HOMA-IR values were higher during the first half of pregnancy (P < 0.001). Nevertheless, the L does showed higher mean insulin concentrations than FO rabbits (P < 0.01) and the lowest glucose clearance (P < 0.01) during pregnancy. On the other hand, pregnant FO rabbits showed the lowest glucose concentrations (P < 0.05) and the lowest Homeostasis model assessment values for insulin resistance (HOMA-IR, P < 0.05) as well as a faster restoration of baseline glucose levels following glucose load (P < 0.001). Before and during pregnancy, the BW of the rabbits was positively related to fasting sample- and tolerance test-derived indices of insulin resistance (P < 0.05) suggesting that a high pre-pregnancy BW predisposes to gestational insulin resistance. Linseed supplementation increased BW and predisposed to insulin resistance during pregnancy; whereas, fish oil improved insulin sensitivity without significant changes in BW

Effects of housing system on welfare and milk yield and quality of Girgentana goats

Effetti del sistema di stabulazione sul benessere e sulla produzione di latte di capre Girgentane \u2013 La stabulazione in poste individuali, in uso per la razza Girgentana, per evitare che le capre possano procurarsi lesioni con le corna, viene confrontata con la stabulazione libera, valutando il grado di benessere e la produttivit\ue0 di 40 capre. Le Girgentane tenute alla posta hanno fatto rilevare buone condizioni di benessere e un pi\uf9 elevato livello produttivo, collegati alla mancanza degli effetti stressanti della gerarchia sociale ed alla possibilit\ue0 dell\u2019integrazione individuale. Tuttavia, assicurando adeguata igiene e sufficiente spazio, le Girgentane hanno mostrato di poter adattarsi anche alla stabulazione libera, che ha offerto maggiori possibilit\ue0 di movimento e relazioni sociali, e ha indotto una migliore risposta immunitaria; la minore esigenza di manodopera compenserebbe il pi\uf9 basso livello produttivo registrato con tale sistema.In the past years, in Sicily, goats of the Girgentana breed have decreased so drastically in number that they risked extinction. Among the causes, particular blame can be laid at the traditional housing system, in which the goats, after coming back from pasture, were tethered in individual wooden stalls. Such a system is still considered necessary by breeders in order to avoid aggressive and harmful behaviour on the part of the animals, due to the presence of their long horns (Giaccone et al., 1994). This belief negatively interferes with the action recently initiated for the recovery and regeneration of the breed (Portolano et al., 2002); in fact, the tie stalls housing, increasing manpower, limits the increase in size in herds of Girgentana goats. On the other hand, the biological production method does not admit the tie stall housing, but imposes a housing system that ensures that animals have freedom of movements and can express normal social behaviour. The present study aims to contribute to the development of the Girgentana breed, evaluating its adaptation to free-housing. Goats tethered in stalls and free-housed in a straw-bedded pen were compared by assessing their behavioural, immunological, endocrine and productive responses

Effect of LPS-induced inflammatory state on some aspects of reproductive function of rabbit does

Effetto dell\u2019infiammazione indotta con LPS su alcuni aspetti della funzione riproduttiva nelle coniglie. Scopo della ricerca \ue8 stato quello di studiare un modello d\u2019induzione sperimentale di infiammazione con lipopolisaccaridi (LPS) microbici nella coniglia fattrice e l'eventuale effetto sulla risalita degli spermatozoi. Due gruppi di 6 coniglie fattrici sono state inoculate per via intra-peritoneale rispettivamente con LPS di E. coli 0127:B8 (100 \ub5g/kg peso vivo), o con soluzione fisiologica (controllo). Sono stati rilevati per 72 ore temperatura rettale e il numero dei leucociti; dopo inseminazione artificiale \ue8 stata valutata la risalita degli spermatozoi nel tratto riproduttivo femminile e la situazione ovarica. L\u2019infiammazione sperimentale ha indotto un rilevante incremento della temperatura rettale e sostanziali modifiche a livello di leucociti che sono comunque scomparse entro 72 ore. Anche il numero di spermatozoi risaliti \ue8 stato significativamente pi\uf9 basso a livello di corna uterine e addirittura nullo a livello dell\u2019ovidutto. In conclusione si pu\uf2 affermare che \ue8 possibile costruire un modello d\u2019induzione dello stato infiammatorio nella coniglia mediante inoculazione intra-peritoneale di 100 \ub5g LPS/kg di peso vivo.The efficiency of the cycled production system in rabbit farms is greatly conditioned by the fertility rate of does. Nulliparous does generally exhibit high fertility rate (Castellini et al., 1998), whereas the reproductive performances of multiparous does goes down. One reason of this reduction is related to the use of intensive reproductive rhythms which implies an overlapping between lactation and insemination which often produces a severe energy deficit. As in other mammals, lactation shows a strong hormonal antagonism with the reproductive activity. An other cause of hypo-fertility depends on the sanitary condition of does. Genital tract inflammation and/or infection is one of the major causes of infertility (Gram et al., 2002) and often determined by incorrect practices of artificial insemination (AI). It has been demonstrated that uterine infection negatively affects fertility (Facchin et al., 1999) and prolongs the life span of corpora lutea (Boiti et al., 1999) due to uterine leukocytes infiltration, reduced prostaglandins synthesis and increased spermatozoa reabsorption. Lipopolysaccarides (LPS), constituents of the Gram-negative germ wall, are potent stimulators of prostaglandins synthesis and are widely used to simulate inflammation in several district and organs. The aim of the paper was to verify the effect of an LPS-induced inflammatory state on some aspects of reproductive function of non-lactating rabbit does

Influence of different eCG doses on sexual receptivity and productivity of rabbit does

[EN] The aim of this study was to examine sexual receptivity and productivity of does injected 48 h before insemination with 8 or 25 IU of eCG (groups 8 and 25, respectively) in comparison with a control group (no injection, group 0). One hundred twenty four does were inseminated during 11 consecutive cycles (reproduction rythm: 35 d; inseminations: 4 d post partum and weaning: 28 d post partum). In comparison with the control group, eCG signifi cantly improves the receptivity of does (60.3 vs 80.5 and 79.8%; P<0.001), kindling rate (70.4 vs 80.9 and 79.4%; P=0.030) and the number of weaned rabbits/insemination (5.9 vs 7.1 and 7.1; P=0.008) for group 0, 8 and 25 respectively, during the whole experiment. eCG effi ciency is not obviously demonstrated for primiparous and non-lactating does. Authors conclude that only an 8 IU dose is able to improve 62% the productivity (measured as weaned rabbits per insemination) of multiparous and lactating does inseminated 4 d post partum.Theau-Clément, M.; Lebas, F.; Boiti, C.; G. Brecchia, G.; Mercier, P. (2010). Influence of different eCG doses on sexual receptivity and productivity of rabbit does. World Rabbit Science. 16(2). doi:10.4995/wrs.2008.62816

Expression patterns of cytokines, p53 and nitric oxide synthase enzymes in corpora lutea of pseudopregnant rabbits during spontaneous luteolysis

The gene expressions for macrophage chemoattractant protein-1 (MCP-1), interleukin (IL)-1 beta, IL-2 and p53 were examined by semi-quantitative RT-PCR in corpora lutea (CL) of rabbits during spontaneous luteolysis at days 13, 15, 18 and 22 of pseudopregnancy. In the same luteal tissue, total activity of nitric oxide (NO) synthase (NOS) and genes for both endothelial (eNOS) and inducible (iNOS) isoforms were also analysed. From day 13 to 15, MCP-1 and IL-1 beta mRNA levels rose (P &lt; or = 0.01) almost 2-fold, and the transcript for p53 almost 8-fold, but then all dropped (P &lt; or = 0.05) from day 18 onward. IL-2 mRNA abundance was higher (P &lt; or = 0.01) on day 13 and then gradually declined. During luteolysis, eNOS mRNA decreased 40% (P &lt; or = 0.05) by day 15, but thereafter remained unchanged, while iNOS mRNA was barely detectable and did not show any clear age-related pattern throughout the late luteal stages. Total NOS activity progressively increased (P &lt; or = 0.01) from day 13 to 18 of pseudopregnancy and then dropped to the lowest (P &lt; or = 0.01) levels on day 22. Luteal progesterone content also declined during CL regression from 411 to 17 pg/mg found on days 13 and 22 respectively, in parallel with the decrease in blood progesterone concentrations. These data further support a physiological role of NO as modulator of luteal demise in rabbits. Locally, luteal cytokines may be involved in the up-regulation of NOS activity, while downstream NO may inhibit steroroidogenesis and induce expression of p53 gene after removal of the protective action of progesterone

High plasmatic progesterone levels at insemination depress reproductive performances of rabbit does

The aim of this experiment was to quantify the frequency of the high progesterone syndrome at the moment of insemination and to study the influence of progesterone level (P4) on receptivity and reproductive performances of primiparous and secondiparous rabbit does. A total of 422 primiparous INRA 0067 were inseminated twice at an interval of 42 days. Prior to artificial insemination (AI), sexual receptivity of the does was tested in the presence of a vasectomised buck and, just after AI, blood samples were collected to determine progesterone concentration by RIA. The mean plasma progesterone concentration was 1.8\ub13.4 ng/ml and significantly depended on parity (primiparous: 2.2\ub13.7 ng/ml, secondiparous: 0.9\ub12.2 ng/ml, P&lt;0.001). At the following AI, 78% of pseudopregnant rabbit does returned to the basal level of oestrous condition, demonstrating that the pseudopregnancy is a reversible process. The overall percentage of pseudopregnant does (P4 651 ng/ml) was 25.9%, but it was differently (P&lt;0.001) distributed between primiparous (31.2%) and secondiparous does (12.2%). Moreover, primiparous lactating females were more frequently pseudopregnant than non-lactating ones (36.5 vs. 18.9% respectively, P&lt;0.001). The progesterone level of primiparous does was related to the lactation status (2.5\ub13.8 vs. 1.5\ub13.2 ng/ml, respectively for lactating and non-lactating, P&lt;0.001). The receptivity was highly related to the level of progesterone (P4&lt;1: 74.1%, 1 64P4&lt;6: 79.1% vs. P4&gt;6: 56.3%, P=0.006). Also the kindling rate was significantly influenced by progesterone concentrations. Non-pseudopregnant does (P&lt;1 ng/ml) had the highest fertility rate (79.0%) but when the progesterone concentration increased from 1 64P4&lt;6 to P4&gt;6 ng/ml, the fertility decreased from 68.1 to 37.4%, respectively (P&lt;0.001). Consequently, the productivity at birth was highly depressed when the progesterone level was over 6 ng/ml (9.5 and 8.6 vs. 4.5 number of born alive rabbits/AI, for P4&lt;1, 1 64P4&lt;6 and P4&gt;6 respectively, P&lt;0.001). The productivity of pseudopregnant and nonreceptive females was very poor in comparison with pseudopregnant receptive does (0.4 vs. 9.5 born alive rabbits/AI). The productivity at birth was also highly (P&lt;0.001) influenced by the physiological status of the does. Primiparous non-lactating does produced the highest number of born alive rabbits/AI, whereas primiparous lactating does had the lowest productivity at birth (9.9 vs. 5.6), secondiparous lactating being intermediate (7.1). In conclusion, the high progesterone syndrome evaluated at the moment of insemination occurred in 25.9% of females and had a strong negative impact on receptivity and reproductive performance of rabbit does