Prolactin and prolactin receptor expression in the HPG axis and crop during parental care in both sexes of a biparental bird (Columba livia)

During breeding, multiple circulating hormones, including prolactin, facilitate reproductive transitions in species that exhibit parental care. Prolactin underlies parental behaviors and related physiological changes across many vertebrates, including birds and mammals. While circulating prolactin levels often fluctuate across breeding, less is known about how relevant target tissues vary in their prolactin responsiveness via prolactin receptor (PRLR) expression. Recent studies have also investigated prolactin (PRL) gene expression outside of the pituitary (i.e., extra-pituitary PRL), but how PRL gene expression varies during parental care in non-pituitary tissue (e.g., hypothalamus, gonads) remains largely unknown. Further, it is unclear if and how tissue-specific PRL and PRLR vary between the sexes during biparental care. To address this, we measured PRL and PRLR gene expression in tissues relevant to parental care, the endocrine reproductive hypothalamic-pituitary- gonadal (HPG) axis and the crop (a tissue with a similar function as the mammalian mammary gland), across various reproductive stages in both sexes of a biparental bird, the rock dove (Columba livia). We also assessed how these genes responded to changes in offspring presence by adding chicks mid-incubation, simulating an early hatch when prolactin levels were still moderately low. We found that pituitary PRL expression showed similar increases as plasma prolactin levels, and detected extra-pituitary PRL in the hypothalamus, gonads and crop. Hypothalamic and gonadal PRLR expression also changed as birds began incubation. Crop PRLR expression correlated with plasma prolactin, peaking when chicks hatched. In response to replacing eggs with a novel chick mid-incubation, hypothalamic and gonadal PRL and PRLR gene expression differed significantly compared to mid-incubation controls, even when plasma prolactin levels did not differ. We also found sex differences in PRL and PRLR that suggest gene expression may allow males to compensate for lower levels in prolactin by upregulating PRLR in all tissues. Overall, this study advances our understanding of how tissue-specific changes in responsiveness to parental hormones may differ across key reproductive transitions, in response to offspring cues, and between the sexes.

Pharmacokinetic of sulfaclozine in broiler chickens

In this study, 30-day-old, 14 male broiler chickens were used. Two groups, each comprising 7 animals, were established. While each animal included in the first group was administered sulfaclozine at a dose of 60 mg/kg bw by intravenous route (IV), group 2 was administered sulfaclozine at the same dose but by intracrop route (IC). In group 1, serum sulfaclozine concentrations at 0.083, 0.50, 2, 6, 24 and 72h were determined to be 99.62+/-3.31, 83.50+/-4.22, 72.68+/-5.02, 58.43+/-5.39, 38.66+/-4.04 and 13.14+/-1.64 microg/ml, respectively, via HPLC. In group 2, serum drug concentrations at 0.083, 0.50, 2, 6, 24 and 72h were determined as 4.33+/-0.45, 7.95+/-0.72, 16.46+/-2.68, 22.88+/-3.00, 16.03+/-3.53 and 5.74+/-0.98 microg/ml, respectively. Statistical analyses revealed that, of all the parameters studied, only A(1)( *), A(2)( *), alpha, beta, t(1/2)(alpha), t(1/2)(beta), MRT, Vd(area), k(12), k(21), AUC(0-->72) and AUC(0-->infinity) differed significantly between the groups (p<0.05). Compared to intravenous administration, significant increase in t(1/2)(alpha), t(1/2)(beta), MRT and Vd(area), and significant decrease in A(1)( *), A(2)( *), alpha, beta, k(12), k(21), AUC(0-->72) and AUC(0-->infinity) were observed in the group, which was administered sulfaclozine by intracrop route.

Chronic regurgitation in a cockatiel (Nymphicus hollandicus) with a trichobezoar

Crop disorders are very common in small psittacine birds. Psittacine birds are very curious and like chewing on different materials. Therefore, they are predisposed to ingest foreign material. In the literature only very few cases have been reported. This case report describes the clinical examination, the diagnostic workup and the ingluviotomy in a cockatiel with a bezoar in the crop.

Passage rate through the anterior digestive tract of broiler chickens fed on diets with ground and whole wheat

1. Birds were fed diets containing ground or whole wheat and titanium dioxide for 10 min, followed by dissection of 4 birds per treatment after 30, 60, 90, 120, 150 and 180 min. 2. The crop, proventriculus and gizzard, duodenum, jejunum, and ileum from each bird were dried and combusted, and titanium content in each section was determined. 3. Significant amounts of titanium were found in the small intestine of the birds as soon as 30 min after being given feed containing titanium, and significant amounts had passed the small intestine after 120 to 150 min. 4. Titanium contents equivalent to approximately 5 g feed were eliminated from the gizzard per hour independently of whether ground or whole wheat was used. Thus, a hypothesis that the use of whole grain would slow down passage rate through the upper digestive tract was not supported by the current results.

The roles of stimuli from young, previous breeding experience, and prolactin in regulating parental behavior in ring doves (Streptopelia risoria)

In addition to stimulating crop "milk" formation in ring doves, prolactin (PRL) may promote the parental regurgitation behavior that transfers this "milk" to the young at the time of hatching. Although earlier studies suggest that previous breeding experience is an important modulator of PRL-induced parental regurgitation behavior in ring doves, the ways in which experience, hormones, and stimuli from young interact to promote parental behavior have not been well characterized in this species. In the first study, untreated, nonbreeding female doves with and without previous breeding experience were given 10 daily parental behavior tests (2 h/day) with a hungry 5- to 10-day-old foster squab. Experienced females exhibited a higher incidence of regurgitation behavior, defensive behavior, and crouching or sitting in the nest than did inexperienced females. In a second study, nonbreeding females were given 10 daily tests for parental behavior while they received sc injections of ovine PRL or vehicle. Prolactin reduced squab-directed aggression and increased the incidence of regurgitation feeding behavior of foster squabs in both experienced and inexperienced females. However, the average number of regurgitation feeding acts displayed by those PRL-treated females that showed the behavior was over eight times higher in experienced females than in inexperienced females. Previous experience also enhanced the stimulatory effects of PRL on defensive behavior and crouching or sitting in the nest. The parental behavior exhibited by nonbreeding, PRL-treated experienced females was qualitatively and quantitatively similar to that observed in normally breeding females during a single test with their own hungry 5- to 10-day-old squabs. These findings indicate that PRL and previous breeding experience both enhance the parental responsiveness of nonbreeding female doves and that under optimal hormonal, experiential, and squab exposure conditions, nonbreeding doves exhibit levels of parental activity that rival those of normally breeding parents.

Relationship between feed withdrawal and viscera condition of broilers

This study was conducted to investigate the effects of feed withdrawal on the viscera of commercial broilers. Birds were withdrawn from feed 0, 3, 9, 12, 14, 16, or 18 h before slaughter. Crop and gizzard contents were determined after dissection, and intestinal shape and villi were subjectively scored. Raw liver color was measured colorimetrically. Length of feed withdrawal (time) and its interaction with grower (time by grower) and replication (time by replication) had a significant effect (P < 0.05) on gizzard contents, intestinal shape, and villi; however, time by grower and time by replication did not affect the crop contents or the incidence of bile contamination in the digestive tract. Results also suggested that the integrity of the intestines declined after 12 to 14 h feed withdrawal, as indicated by heavy intestinal sloughing. Color analyses of livers showed that length of feed withdrawal did not affect lightness (L* values), but livers became less red (lower positive a*) as feed withdrawal time increased. It was concluded that length of feed withdrawal significantly affected the gastrointestinal tract; however, variation in the appearance of the liver could not be attributed solely to broiler feed withdrawal time.

Treatment of acute lead ingestion in a juvenile macaw

A juvenile domestic green-winged macaw was admitted to the veterinary clinic within an hour of ingestion of lead drapery weights. Radiopaque objects were evident in the crop and ventriculus. The bird was anesthetized, and the crop was lavaged to remove lead fragments. Because lead fragments remained in the ventriculus after lavage, chelation treatment was instituted. Serial radiography was done on days 2, 5, 9, and 14 to determine passage of the lead. By day 14, lead fragments were not visible radiographically. The macaw did not have ill effects from the lead ingestion or from medical treatments. Because this bird had been observed ingesting the lead weights, treatment was for foreign body ingestion initially and for lead ingestion secondarily.

Pharmacokinetic profile and tissue distribution of monensin in broiler chickens

1. The pharmacokinetics of monensin, including half-life, apparent volume of distribution, total body clearance, systemic bioavailability and tissue residues were determined in broiler chickens. The drug was given by intracrop and intravenous routes in a single dose of 40 mg/kg body weight. 2. Following intravenous injection the kinetic disposition of monensin followed a two compartments open model with absorption half life of 0.59 h, volume of distribution of 4.11 l/kg and total body clearance of 28.36 ml/kg/min. The highest serum concentrations of monensin were reached 0.5 h after intracrop dosage with an absorption half-life of 0.27 h and an elimination half life of 2.11 h. The systemic bioavailability was 65.1% after intracrop administration. Serum protein-binding tendency of monensin calculated in vitro was 22.8%. 3. Monensin concentrations in the serum and tissues of chickens after a single intracrop dose of pure monensin (40 mg/kg body weight) were higher than those after feeding a supplemented monensin premix (120 mg/kg) for 2 weeks. Monensin residues were detected in tested body tissues, collected 2, 4, 6 and 8 h after oral administration. The highest concentration was found in the liver. In addition, monensin residues were detected only in liver, kidney and fat 24 h after the last oral dose. No monensin residues could be detected in tissues after 48 h, except in liver which cleared completely by 72 h.

Effects of feeding by crop intubation on energy metabolism and physical activity in domestic cockerels

1. Heat production and physical activity were measured in cockerels given the same amount of food either conventionally or by direct intubation into the crop. 2. The thermogenic effect of feeding (heat increment per unit weight of food) was about 30% less with tube-feeding. 3. The difference in heat increment of feeding, and therefore in efficiency of energy utilisation, was entirely attributable to the circumvention of feeding activity by intubation.

The effect of light and environmental temperature on broiler digestive tract contents after feed withdrawal

Contamination from the digestive tract is a persistent problem in broiler processing. Two experiments were conducted to determine the effects of lighting and environmental temperature on quantity of crop, gizzard, and small intestine contents during feed withdrawal. Broilers were on litter with a feeding regimen of 1.5 h on feed and 4.5 h off feed for 1 or 2 days. The withdrawal period began at the end of a 1.5-h feeding period. In the first experiment, broilers were cooped or left on the floor with and without lights. Crop contents of lighted broilers at 21 C were reduced 2 h after feed withdrawal for broilers on litter and in coops. In another experiment, broilers on litter were maintained at 18 and 27 C in light or in darkness. Lighting reduced crop contents 4 h after feed withdrawal but increased the contents of the small intestine 2 h after feed withdrawal at both temperatures. These results indicate that crop clearance is improved by lighting both before and after cooping.

Alimentary foreign body in an Amazon parrot

An Amazon Parrot regurgitated and drooled and had blood in its droppings. Abdominal palpation revealed several small, spherical masses. Positive-contrast radiographs clearly delineated the objects. With the bird under halothane anesthesia and the beak held open, a sponge forceps was used to extract a string of 25 beads from the alimentary tract. Gentamicin and dexamethasone were given IM and recovery was uneventful.

Crop impactions in bobwhite quail in Louisiana

Crop impactions (solid, hard masses of seeds) caused by seeds of clammy weed (Cuphea carthagenensis) were found in bobwhite quail (Colinus virginianus) killed during the 1965-71 hunting seasons in Louisiana. Emaciation and weakened condition were associated with the presence of crop impactions in two quail, suggesting that physical obstruction of the crop by impactions may be of significant pathologic consequence.