Apparent lack of efficacy of toltrazuril against Eimeria species affecting brown kiwi (Apteryx mantelli) at a captive rearing facility

AIM: To assess the efficacy of toltrazuril against the Eimeria spp. affecting brown kiwi (Apteryx mantelli).

METHODS: Droppings were collected from three brown kiwi, aged <6 months old, at a captive rearing facility in the North Island of New Zealand, between 22 February and 20 April 2017, on 14 sampling dates. Only droppings (n=30) that were excreted between 03:00 and 07:00, as determined using video surveillance, were included for analysis, reflecting the peak time for shedding of coccidial oocysts for brown kiwi. Oocysts were quantified in each sample and Eimeria species identified on the basis of oocyst morphology. All samples were collected between 2 and 10 days after the birds had been treated with 25?mg/kg toltrazuril.

RESULTS: Eimeria spp. oocysts were identified in 28/30 individual samples and on 14/14 sampling dates. Oocyst counts varied from 0 to 328,080 oocysts per gram (opg), and at least one oocyst count >10,000 opg was measured on 12/14 sampling dates. Three species of Eimeria were observed, with Eimeria apteryxii and E. kiwii most commonly encountered, whereas only one sample contained E. paraurii.

CONCLUSIONS AND CLINICAL RELEVANCE: In the three birds monitored at this research site, there was a high abundance of E. apteryxii and E. kiwii oocysts in droppings despite recent administration of toltrazuril. These results suggest that the populations of Eimeria spp. affecting brown kiwi at this location appear to possess an ability to survive exposure to toltrazuril. Toltrazuril is widely used at captive rearing facilities to limit the effects of coccidiosis in juvenile kiwi. If a lack of efficacy is confirmed, it will be necessary to investigate alternative treatment regimens alongside broader environmental management strategies.     

Anoestrus in the Dog: a Fascinating Story

In the bitch, progression from early to late anoestrus is characterized by a higher amplitude and a larger number of gonadotrophin-releasing hormone (GnRH) pulses generated by the hypothalamus, an increase in the sensitivity of the pituitary to GnRH, and an increase in ovarian responsiveness to gonadotrophins. An increase in basal plasma follicle-stimulating hormone (FSH) concentration is a critical event required for initiation of folliculogenesis. A period of increased luteinizing hormone pulsatility has been reported shortly before the onset of pro-oestrus. Apart from these changes in the hypothalamic-pituitary-ovarian axis, there is also involvement of dopaminergic influences in the initiation of a new follicular phase in the bitch. Administration of the dopamine-agonists bromocriptine and cabergoline shortens the anoestrus and is associated with a decrease in the plasma prolactin concentration, suggesting that the shortened anoestrus is the result of suppression of prolactin secretion. Yet, the anoestrus is not shortened in bitches treated with metergoline, a drug, which in a low dosage lowers the plasma prolactin concentration via a serotonin-antagonistic pathway. In addition, under physiological conditions low plasma prolactin concentrations are found during the entire anoestrus. Furthermore, a low dosage of bromocriptine, insufficient to cause a decrease in the plasma prolactin concentration, prematurely induces folliculogenesis. These observations indicate that not the decrease in the plasma prolactin concentration, but another dopamine-agonistic influence plays a critical role in the transition to a new follicular phase. The dopamine-agonist induced shortening of the anoestrus is associated with a rapid rise in the basal plasma FSH concentration, similar to what is observed during the physiological late anoestrus. This observation underlines the importance of an increase in the circulating plasma FSH concentration in the initiation of folliculogenesis in the bitch.     

Detection and localization of regucalcin in spermatozoa of water buffalo (Bubalus bubalis): A calcium‐regulating multifunctional protein

Regucalcin (RGN) is a calcium‐regulating, anti‐apoptotic, antioxidative and antiproliferative multifunctional protein predominantly seen in liver and kidney. All these functions are very crucial during spermatogenesis and sperm maturation process until fertilization of the ovum. Although many studies have reported the wide distribution of regucalcin in the male reproductive tract of the rat, human and bovine, its presence in spermatozoa is yet to be demonstrated wherein calcium has a pivotal role in the transport, capacitation, acrosomal reaction and further fusion with ova. Here, we detected the expression of regucalcin mRNA and protein in buffalo spermatozoa using real‐time PCR and Western blot, respectively. The study detected two new regucalcin isoforms of 44 kDa and 48 kDa size along with the reported 34‐kDa, 28‐kDa and 24‐kDa isoforms, wherein the 34‐kDa isoform was found to be membrane associated in spermatozoa. Further, immunocytochemistry study localized the regucalcin protein in the acrosomal region of the caudal and ejaculated buffalo spermatozoa while it was detected in both cytoplasm and acrosomal region of testicular spermatozoa. This discovery of RGN in spermatozoa and localization in the acrosomal region will help to focus researchers to see its role in calcium‐related functions like capacitation, acrosomal reaction and membrane fusion. Overall, regucalcin may be a new fertility marker in buffalo and can be utilized for infertility treatments.     

Phosphorus uptake and use efficiency in different varieties of bread wheat (Triticum Aestivum L)

Thirty spring wheat varieties were evaluated and classified into eight different groups on the basis of their grain yield performance and phosphorus (P) uptake using Metroglyph analysis. Significant variability was observed for grain and biomass yield, plant height, P content in grain and straw, total P uptake and phosphorus harvest index and P use efficiency traits. Varieties WH 711 and PBW 343 exhibited high grain yield as well as high P uptake (HGY-HP). WH 283 and UP 2425 with high index score of 19 and 16 respectively, constituted the high grain yield-medium P uptake (HGYMP) group. Both these varieties, though had similar grain yield of 5348 kg/ha, but WH 283 (12.64 kg/ha) utilized much lower P as compared to UP 2425 (16.94 kg/ha). Moreover, WH 283 (81.64) also showed higher values for phosphorus harvest index (PHI) than UP 2425 (67.88%). P uptake of WH 283 was comparable with that of Raj 3765 (10.78 kg/ha) and grouped into high grain yield and low P uptake (HGY-LP) group. The grain yield performance of these two varieties with a relatively low P uptake is reflected in their high index score for P use efficiency thus, earmarking them for low P regimes. Variety HW 2006, despite low grain yields of 4665 kg/ha had high index score of 16 due to its higher value for Phosphorus Biological (PBER) and Economic Yield (PEER) Efficiency Ratio as it has effected least (7.18 kg/ha) P mobilization. In addition high P translocation in the grain was also observed for this variety. Inter-mating of genotypes like HW 2006, UP 2338 and HW 2016 with those belonging to HGY-HP (PBW 343 and WH 711) and HGY-LP (Raj 3765 and WH 283) would be an ideal strategy to develop the cultivars for efficient phosphorus use.     

Research progress on the role of melatonin and its receptors in animal reproduction: A comprehensive review

Melatonin and its receptors play a crucial role in the regulation of the animal reproductive process, primarily in follicular development. However, the role that melatonin performs in regulating hormones related with reproduction remains unclear. Melatonin and its receptors are present both in female and male animals’ organs, such as ovaries, heart, brain and liver. Melatonin regulates ovarian actions and is a key mediator of reproductive actions. Melatonin has numerous effects on animal reproduction, such as protection of gametes and embryos, response to clock genes, immune‐neuroendocrine, reconciliation of seasonal variations in immune function, and silence or blockage of genes. The growth ratio of reproductive illnesses in animals has raised a remarkable concern for the government, animal caretakers and farm managers. In order to resolve this challenging issue, it is very necessary to conduct state‐of‐the‐art research on melatonin and its receptors because melatonin has considerable physiognomies. This review article presents a current contemporary research conducted by numerous researchers from the entire world on the role of melatonin and its receptors in animal reproduction, from the year 1985 to the year 2017. Furthermore, this review shows scientific research challenges related to melatonin receptors and their explanations based on the findings of 172 numerous research articles, and also represents significant proficiencies of melatonin in order to show enthusiastic study direction for animal reproduction researchers.     

Identification of Chlamydia gallinacea in a parrot and in free‐range chickens in Australia

Chlamydia gallinacea is a recently described bacterial species in a genus known to infect and cause disease in animals and humans. Our report describes the identification of C. gallinacea infection in free‐range laying chickens (Gallus gallus) in Australia, and the identification of C. gallinacea infection in a parrot, a wild Australian galah (Eolophus roseicapillus). There is currently little knowledge of the effects of C. gallinacea infection on avian hosts, but it has been linked to respiratory disease in humans and could potentially cause similar disease in other species. Our report highlights the need for further study and surveillance of Chlamydia species in both wild and domestic hosts in Australia.