Reproductive Technologies Used in Female Neo-Tropical Hystricomorphic Rodents

This is the second of two literature reviews that focuses on the female reproductive anatomy and reproductive technologies used in selected neo-tropical hystricomorphic rodents. The rodents chosen included the agouti (Dasyprocta leporina), the capybara (Hydrochoerus hydrochaeris), and the paca (Cuniculus paca). Over seventy references were used, spanning the years 1919–2021. Knowledge of the reproductive tract is important in understanding any unique features, which may affect the use of reproductive technologies. Some unique characteristics common to these species included the presence of a vaginal closure membrane and a lobulated placenta with a vascular sub-placenta. The capybara had hyperpigmentation of the vagina that was unique to each individual, while the agouti and paca had accessory corpora lutea, in addition to the main one. Some reproductive technologies have been used, with attempts at estrous induction and synchronization taking place within the past five years. Even though most work has been done over the past twenty years, there is still a dearth of information.

Reproductive Technologies Used in Male Neo-Tropical Hystricomorphic Rodents

This review, which is the first of two, focuses on the male reproductive anatomy and reproductive technologies used in Neo-tropical hystricomorphic rodents with the potential for domestication, which are the agouti (Dasyprocta leporina), the capybara (Hydrochoerus hydrochaeris) and the paca (Cuniculus paca). We consider over seventy references spanning from 1965 to 2020, with the majority of work being done in the past twenty years. Knowledge of the reproductive tract and reproductive technologies is critical to the conservation and preservation of these species. Although all three animals had similarities in their anatomy, such as no overt scrotums and testes located intra-abdominally in the inguinal region, some had unique features-for example, the agouti and the paca had penile spines, and two lateral penile cartilages. High spermatogenic efficiency was noted in the agouti and the paca, making them good candidates for increasing their reproductive performance in conservation programs. A review of the literature has shown that there is increasing work taking place on the reproductive technologies used in these animals; however, a lot of work is still lacking, as, to the author's knowledge, standard protocols and artificial insemination procedures are yet to be established.

Teaching of Veterinary Parasitology to University students in Trinidad, West Indies; are our local wildlife species neglected?

Parasites of veterinary importance have been heavily focused on domesticated livestock that was introduced into the neo-tropics. The text used in the teaching parasitology to veterinary students in Trinidad has only investigated the parasites of domesticated species. In the reviewed veterinary parasitology text no mention was made on the parasites that affect wild neo-tropical animals. Information on wild neo-tropical animals had to be sourced from texts on the management of wild life animals in the Neotropics. The texts that were reviewed in this document spanned from the mid-1950s to 2020. The information presented in this review reveals the exhaustive work done on the parasites of domesticated species but also revealed little information on neo-tropical animals with the potential for domestication. In conclusion, this review reveals the gap of information that is missing from parasitology texts used in the teaching of veterinary students. In the future these parasitology texts can be revised to include chapters on the parasites of neo-tropical animals with the potential for domestication. At present students that graduate from the veterinary parasitology course has little information on the parasites of animals which are present in their 'backyards'.

Anthelmintic usage on the performance of the Agouti (Dasyprocta leporina) reared intensively in Trinidad and Tobago, West Indies

Anthelmintic drugs have been used strategically in livestock reared in the tropics. These drugs have been used in the treatment of endoparasitism which have resulted in an increase in the animals' performance. The agouti (Dasyprocta leporina) is a neo-tropical rodent with the potential for domestication and has been farmed intensively in Trinidad. However, the objective of this research was to investigate the effect of anthelmintic use of the growth performance of the agouti. In searching the literature, it was found that this type of study on the agouti has not been done. In this experiment fourteen weaned agoutis weighing 1kg were divided into two groups randomly. The first group (T1) was not given any anthelmintic treatment but the second group (T2) was treated with Endovet Ces® subcutaneously every three months. There were no significant differences (p > 0.05) between the two groups in the carcass weight, weight gain, dressing percentage (hot and cold), heart, lungs, skin, head and feet. However, a significant difference (p < 0.05) was seen between groups in the weight of liver and pluck. To the authors knowledge this is the first time that carcass parameters has been presented in literature. The live weight of the animals at the end of the experiment ranged from 2.4 kg to 2.6 kg and animals had a dressing percentage of 57% to 55%. The results are suggestive that the use of anthelmintic drugs in agoutis reared intensively had no significant effect on weight gain and dressing percentage.

Anthelmintic usage on the Reproductive Parameters in Captive reared Agoutis (Dasyprocta leporina) in Trinidad and Tobago, West Indies

The agouti (Dasyprocta leporina) is a rodent that is found in the Neo-tropical region. This animal is hunted for its meat but has recently been reared in captivity as a source of meat protein in rural communities. A 20-month experiment was carried out to evaluate the effect of an anthelmintic on the reproductive performance of the agouti (Dasyprocta leporina) reared in captivity. This experiment was conducted in the humid tropics of Trinidad and Tobago. Sixteen animals (15 females, 1 male) placed in each of the two treatment groups in a completely randomized study design. In treatment 1 (T1) animals were given subcutaneous injections of Endovet Ces® (Ivermectin/Praziquantel) at 0.2 mg/kg every three months. Treatment 2 (T2) was the negative control group where animals were not exposed to an anthelmintic. Reproductive data were collected at parturition which included birth weight, litter weight, litter size and gender of offspring. The results showed that there was no statistical difference (p > 0.05) between the treatment groups with respect to birth weight, litter weight, litter size and gender. However, agoutis that were dewormed had a higher birth weight (220.24 g vs 209.1 g) and litter weight (369.8 g vs 343 g). The same values were obtained for the litter size (1.7 vs 1.7) and animals that were dewormed had a higher female offspring to male offspring (2.41:1 vs 1.11:1). This experiment demonstrated that the use of an anthelmintic strategically in the management of captive reared agoutis had no statistical effect (p > 0.05) on the reproductive parameters. Therefore, these animals can be kept in captive conditions without being dewormed and produce efficiently with proper feeding and housing management.

Reproductive diseases in captive Agoutis (Dasyprocta leporina)

Reproductive diseases have been well documented in domestic livestock such as sheep, goat, cattle and pigs. However, there is very little information on these diseases in the agouti (Dasyprocta leporina). The agouti is used for its meat in South America and the Caribbean. More recently, intensive farming of this animal is being practiced in the Neotropics. There is dearth of information on dystocia and vaginal prolapses in the agouti. This document reports on three cases of reproductive diseases in captive reared agoutis in Trinidad and Tobago. The first case was a female agouti weighing approximately 3 kg that was in the last stage of pregnancy, which was found dead in its cage. The vulva of the mother had the protruding hind-limbs of the fetus. Necroscopic evaluation of carcass revealed little fat tissue and the mother had two fetuses in the right horn of the uterus. Each fetus weighed approximately 200 g. The fetuses were well formed with fur, teeth and eyes. The placenta was attached to each fetus. The pathological findings suggested that dystocia resulted from secondary uterine inertia which was the cause of death of the adult female agouti. The second case was that of an adult female agouti weighing 2.5 kg. This female had given birth to an offspring three weeks prior and was observed to have had a vaginal prolapse. Surgery was performed and the prolapsed vagina was placed back into the pelvic cavity. Further to this intervention, the vagina prolapsed twice. Subsequent to the re-insertion of the vaginal tissue the agouti was euthanized. The third case was also that of a dystocia. However, the fetuses weighed 235 g and 165 g respectively and were in normal presentation, posture and positioning. The fetus however was unable to pass via the vagina and was trapped in the pelvic cavity. This caused secondary uterine inertia which was the cause of death. The causes of reproductive diseases in these cases are unknown but the feeding management and space allowance given to the agouti in late gestation may be contributing factors.

Breeding and reproductive behaviour of the neo-tropical opossum, Didelphis marsupialis insularis, Allen 1902 under captive conditions

Developing a captive breeding system for the widely hunted Caribbean species of opossum Didelphis marsupialis insularis can greatly aide in the management and conservation of this species in the neo-tropics. Although this species possesses ideal traits for captive breeding in this region (tolerance to high heat and humidity, high reproductive rate, and resistance to disease), challenges due to its aggressive behaviour and limited information on its breeding behaviour have prevented a system from being developed for this species. The present study describes a breeding system, and the reproductive behaviour of this species under captive conditions. Six (1 male; 5 females) adult opossums were maintained and managed for breeding over a ten (10) month period. Pouch litter sizes averaged 5±2.5 with a range of 2 to 8. Gestation length was found to be 13.25±0.96 days and 4 litters (n=23) were successfully weaned at 11-13 weeks. It was found that the male D. m. insularis exhibits behaviours of interest that can serve as indicators for receptivity of the female, and overall, that this species can be successfully reared and bred under captive conditions in the neo-tropics.

Agroecological practices to support tropical livestock farming systems: a Caribbean and Latin American perspective

With global climate changes currently occurring, and particularly given the severe energy and food shortages occurring throughout tropical regions, agroecological (AE) systems are drawing renewed attention as an efficient alternative to intensive models of production, particularly unsuitable in regions of the world such as the Caribbean or Latin America. There is a pressing need to focus on livestock farming systems (LFS) and characterize their potential contributions to global sustainability. A multidisciplinary approach is needed to address these multiple and complex problems. Traditionally, LFS have shown their sustainability high potential. The purpose of this work is to highlight solutions to minimize inputs, by describing some success and diverse case studies through the Caribbean. These systems were analyzed at different levels: animal/function, farm/family, and territory/society. This produced a set of guidelines that help to increase the efficiency of tropical systems, particularly those concerned with (1) choosing the best-suited genotypes, while enhancing population biodiversity; (2) matching the farming system to the available resources, feed, and by-products; (3) steering the whole farming system through reproduction management with no hormonal treatment, while facilitating system reproducibility and increasing performances; (4) controlling health constraints instead of annihilating risks and implement an integrated management design to reduce chemical treatments or increase the use of nutraceuticals; and (5) mitigating climate constraints by using soft techniques. In the second part of this work, some integrated systems are described. The Tosoly farm of Colombia, for instance, is conceived as a totally integrated crop-livestock system, allowing the additional production of energy at the farm level. Thus, it epitomizes the positive impact that livestock can exert upon the environment. The case study of Haiti indicates how AE practices can help in designing a pro-poor sustainable milk production system. It concerns an entire dairy sector built all over the country on the basis of micro-units of milk production and processing.

Mammary Diseases in a Captive Reared Agouti (Dasyprocta leporina) in Trinidad

The agouti (Dasyprocta leporina) is a neotropical rodent that is utilized for its meat by hunters as well as wildlife farmers. There is a dearth of information on infectious diseases that affect these animals. At present, there has been no recording in the literature on diseases of mammary tissue in these animals. This case reported on the abnormal mammary enlargement of a four year old female agouti post-partum. Blood, milk and tissue samples were taken for diagnostics to determine the cause of disease. Histological samples confirmed the swelling of the mammary gland as a diffuse mammary hyperplasia. Hematological values obtained were within the reference range of agoutis reared in captivity. The milk samples that were taken cultured Staphylococcus spp. in one mammary gland (left inguinal). The cultured bacteria in the milk samples confirmed this animal had mastitis. The bacterial cultured (Staphylococcus aureus) was sensitive to tetracyclines, ampicillin, trivetrin and ceftiofur. To the authors’ knowledge, this is the first record in the literature on mastitis in the agouti. Thus, this information will add to the knowledge of diseases in captive reared agoutis.

Natural Habitat, Housing, and Restraint of Six Selected Neotropical Animals in Trinidad and Tobago with the Potential for Domestication

This paper highlights the natural habitat, housing, and restraint needs of 6 Neotropical animals that are found in Trinidad and Tobago with the potential for domestication: agouti (Dasyprocta leporina), lappe/paca (Cuniculus paca/Agouti paca), capybara (Hydrochoerus hydrochaeris), manicou/opossum (Didelphis marsupialis insularis), collared peccary (Tayassu tajacu/Pecari tajacu), and red brocket deer (Mazama americana). The year of the earliest reference cited was 1950 and the most recent was 2018, with over 100 references being used. The average density, home range size, social group, and housing requirements were also examined as these factors would play a role in designing enclosures. A number of different physical and chemical restraint techniques were also discussed. Information from other species within the same genus was incorporated as some of the animals did not have sufficient literature.

Dystocia in a Captive Reared Agouti (Dasyprocta leporina) in Trinidad and Tobago, West Indies

Dystocia is a complication that occurs at parturition either due to foetal or maternal factors. This condition has been well studies in domesticated species. However, there is very little information on dystocia in the agouti (Dasyprocta leporina). The agouti is utilized for its meat in South America and the Caribbean. More recently, farming of these animals intensively is being practiced in the Neo-tropics. This case report attempted to provide some insight into dystocia in the agouti which has been rarely reported in animals in captivity. A female agouti weighing approximately 3 kg (kg), which was in the last stage of pregnancy, was found dead in its cage. The vulva of the animal had the hind-limbs of the offspring protruding. Upon necropsy the animal had little fat reserves and had two foetuses in the right horn of the uterus. The feet of on offspring were dislocated and exposed at the level of the vulva. Each foetus weighed approximately 200 g. The foetuses were well formed with fur, teeth and eyes. The placenta was attached to each of the foetuses. The pathological findings suggested that dystocia resulted in secondary uterine inertia, which was the cause of death of the adult female agouti. To prevent the recurrence of this situation the gestation should be staged (timed) using ultrasonography. Animals which are in their third stage of gestation should be monitored using cameras or with personnel at the facility to assist agoutis which are having difficulties at parturition.

Endoparasites of Selected Native Non-Domesticated Mammals in the Neotropics (New World Tropics)

In this review, information was summarized on endoparasites found in six non-domesticated neotropical animals. These mammals have the potential to be domesticated. The animals included three rodents, agouti (Dasyprocta leporina), lappe (Agouti paca), and capybara (Hydrochoerus hydrochaeris); a marsupial, manicou (Didelphis marsupialis insularis); and an artiodactyl, the collared peccary (Tayassu tajacu/Peccari tajacu) and a ruminant (the red brocket deer, Mazama americana). While there are many descriptions of the parasites present, the majority of publications failed to note the effect of them on the animals. Most information is available on endoparasites of capybara, while the endoparasites of the red brocket deer were the least reported. The manicou was reported to have had the most number of endoparasites, 44 species of parasites were reported, while there were only 24 endoparasites reported in the lappe. The most common parasites found in these neotropical animals were Paraspidodera uncinata, Strongyloides spp., Eimeria spp., Moniezia benedeni, Trichuris spp., Physocephalus spp., and Giardia spp. A large majority of the studies concluded that these animals were reservoirs for parasites that could affect domesticated livestock. Endoparasites of zoonotic significance were Echinoccocus spp., Trichuris spp., Giardia spp., and Cryptosporidium spp.

Omnivorous Behaviour of the Agouti (Dasyprocta leporina): A Neotropical Rodent with the Potential for Domestication

The agouti is a Neotropical rodent which is mainly utilized for its meat in rural communities. Recently, captive rearing of these animals by wildlife farmers have increased in the Neotropics. This short communication consists of observation of feeding behaviour of captive reared agoutis at the University of the West Indies Field Station in Trinidad and Tobago. This is the first time in Trinidad and Tobago that meat consumption and the omnivorous behaviour of the agouti have been documented in the literature. The consumption of chicken (Gallus domesticus) eggs, dead chickens, and a brown dove (Zenaida macroura) by captive reared agoutis was noted. This document described the omnivorous behaviour of the agouti which is primarily considered a frugivorous animal. Similar studies in South America have shown that wild and captive reared agoutis consumed animal matter. Further work must be done on the dietary needs and nutrient requirements of the agouti at different physiological states.

Endoparasites of Domesticated Animals That Originated in the Neo-Tropics (New World Tropics)

This review serves to summarize parasites found in Domesticated animals which were found in the Neo-Tropics. Indigenous domesticated Neo-tropical animals include South American camelids, (Lama gunacoa, Lama glama, Lama pacos, Vicuna vicuna), guinea pigs (Cavia porcellus), chinchillas (Chinchilla lanigera), turkeys (Meleagris gallopavo) and ducks (Cairina moschata, Anas platyrhynchos, Dendrocyga autumnalis). These animals were chosen due to their origin of existence (Neo-tropics) and over time these animals became domesticated and were distributed throughout the world. Over eighty (80) references were collected for this review and the papers spanned over eighty (80) years from 1934 to 2018. The gastrointestinal parasites reported for each animal were tabulated and their effects in the animal noted. Parasites reported in domesticated Neo-tropical animals had little to no effect on wild and free ranging animals with a few cases of illness and decreased productivity. The majority of articles viewed these animals as reservoir host which can infect humans and other domesticated livestock. It must also be noted that research done in the past did not focus on the effect these parasites had on these animals but only observed their potential as reservoirs for parasitic diseases.

Infectious Diseases of Six Non-Domesticated Neo-Tropical Animals In Trinidad and Tobago

This review serves to shed light on some common infectious diseases: their names, prevalence, site of infection and diagnostic tools for identificationof six (6) neo-tropical animals that are found in Trinidad and Tobago with the potential for domestication. These are theagouti(Dasyprocta leporina/ D. agouti), lappe/paca (Cuniculus paca/ Agouti paca), capybara (Hydrochoerus hydrochaeris), manicou/opossum (Didelphis marsupialis insularis), collared peccary (Tayassu tajacu/ Peccari tajucu) and red brocket deer (Mazama americana).There is over Ninety (90) references were used, with the earliest being 1951 and the most recent being in 2017.Where literature was lacking, information from other species within the same genus was incorporated and identified clearly. It was interesting to note that the majority of animals, despite being infected with pathogenic organisms were clinically healthy. In animals that showed clinical signs of disease there was a large quantity of pathogens present. This manuscript sheds some light on the pathogens that may use these animals as natural reservoirs. This review paper also includes many of the earliest identification of these pathogens in Neo-tropical animals in specific geographic regions.

Nutrition of Six Selected Neo-Tropical Mammals in Trinidad and Tobago with the Potential for Domestication

This review highlights the available literature on the nutrition of six neo-tropical animals with the potential for domestication—the agouti (Dasyprocta leporina/D. aguti), lappe (Agouti paca), capybara (Hydrochoerus hydrochaeris), manicou/opossum (Didelphis marsupialis insularis), collared peccary (Peccary tajucu) and the red brokcet deer (Mazama americana). Over 100 references were used, spanning over 100 years. The earliest being 1915 and the most recent being 2018. The references used in this review were synthesized to give a detailed look of the dentition, anatomy of the gastrointestinal tract and type of feed these animals consume. Nutritional requirements of the animals are required to understand what is needed for growth, maintenance and reproduction of each physiological stage. The agouti (D. leporina/D. aguti) was observed to be a monogastric mammal that fed primarily on fruits, seeds, animal matter and practiced caecotrophy. The lappe/paca (C. paca/A. paca) was described as a strict herbivore and a frugivore which practiced caecotrophy, with a diet that varied throughout the year, according to food availability. The capybara (H. hydrochaeris) was found to be the largest known rodent and was described as a semiaquatic hindgut fermenter that practiced caecotrophy. The manicou/opossum (D. marsupialis insularis) was found to be an omnivore with a simple stomach. The collared peccary (T. tajacu) was found to be frugivorous. Their unique stomach enabled them to consume a wide variety of feedstuff, allowing them to be found in a wide range of habitats. The red brocket deer (M. americana), a ruminant, was described as a browser that consumed mainly fruits and seeds and they frequented mineral lick. Knowledge of what they consume in the wild is important, so that we know what to feed in captivity. There is also the need to evaluate captive diets while trying to domesticate these mammals and develop nutrient requirement tables for these neo-tropical animals. Finally, an understanding of the dentition and gastrointestinal tract is important to increase efficiency (nutritional and cost). These six neo-tropical mammals were chosen due to their prevalence as game species in Trinidad and Tobago.

Understanding mammary activity in red-rumped agouti and implications for management and conservation of this Neotropical game species

The red-rumped agouti (Dasyprocta leporina) produces precocial young and is the most hunted and farmed game species in several Neotropical countries. An understanding of the reproductive biology, including the relationship between litter size and teat functionality is crucial for conservation management of this animal. In precocial mammals, as the red-rumped agouti, maintaining maternal contact to learn foraging patterns may be more important than the energy demands and nutritional constraints during lactation and suckling may not play important roles when compared to altricial mammals. Therefore, in this study we evaluated the relationship between mammary functionality with litter size, litter birth weight, and parturition number in captive red-rumped agouti. Functionality was assessed by manual palpation of teats from un-sedated females (N=43). We compared the average birth weight of all newborns, male newborns and female newborns among agoutis with different litter sizes and different parturitions by one way ANOVA's, while Pearson's Chi-squared tests were used to detect relationships between teat functionality, litter size, and parturition number. Parturition number had no effect on the mean birth weight of all young (F0.822, P > 0.05), male young (F0.80, P > 0.05) or female young (F0.66, P > 0.05) in the litters. We found (i) no significant correlations (P > 0.05) between teat functionality and litter size and (ii) no significant correlations (P > 0.05) between teat functionality and parturition number. This suggests that whilst all teat pairs were functional, functionality was a poor indicator of litter size; suggesting that female agouti young may not have a high dependency on maternal nutrition; an possible evolutionary strategy resulting in large wild populations; hence its popularity as a game species.

Anatomical stages of penile erection in the agouti (Dasyprocta leporina) induced by electro-ejaculation

The reproductive system of the male agouti is not well documented. This study describes the specific anatomical features of the free part of the penis occurring during penile erection in the agouti. Electro-ejaculation was used to induce erection in three male agoutis that had previously produced offspring. Results proved that there were four stages in the erection process. Stage 1 involved protrusion of the penis from the preputial orifice. The lateral penile cartilages were then spread (stage 2). During stage 3, there was the blooming of the head of the glans penis (penile flower) and eversion of the intromittent sac. The protrusion of the keratinaceous styles and ejaculation occurred during stage 4. This information could assist in semen collection for use in reproductive techniques for the agouti such as artificial insemination.

Plasma concentration of progesterone and 17beta-estradiol of black-rumped agouti (Dasyprocta prymnolopha) during the estrous cycle

Plasma concentration of progesterone and 17beta-estradiol of black-rumped agouti (Dasyprocta prymnolopha) during the estrous cycle. The agouti is a game animal that have been raised in captivity for conservation and sustainability purposes. However, the management of wild animals in an intensive breeding system requires an assertive knowledge of its reproductive parameters, one of the most important features for production improvement. Besides, little information is available regarding changes in reproductive hormone profiles in agouti. The objective of this study was to evaluate the hormonal profile of progesterone and 17beta-estradiol during the estrous cycle of the agouti (Dasyprocta prymnolopha). The hormones were analyzed by radioimmunoassay. Blood samples were collected without sedation twice a week. The concentrations of progesterone were as follows: proestrus 0.78 +/- 0.39 ng/ml, estrus 2.83 +/- 2.34 ng/ml, metestrus 1.49 +/- 1.24 ng/ml, diestrus 3.71 +/- 1.48 ng/ml. In the estrous phase, an increase in the progesterone level was observed during a period of 24h. The average 17 beta-estradiol levels were as follows: proestrus 2 030.98 +/- 961.00 pg/ml, estrus 1 910.56 +/- 650.54 pg/ml, metestrus 1 724.83 +/- 767.28 pg/ml, diestrus 1 939.94 +/- 725.29 pg/ml. The current results suggest that the progesterone plasma concentration during the estrous cycle in the agouti has a similar increasing, stabilizing and decreasing pattern, as in domestic mammals. Agoutis have two phases of follicular development, as two periods of 17beta-estradiol peaks were observed, the first one in the metestrus and the second during the proestrus. Spontaneous ovulation seems to occur after the progesterone peak, possibly indicating that this hormone is associated with the ovulatory process. A more detailed investigation is needed for better understanding of how progesterone influences ovulation. Studies on the involvement of progesterone in follicular rupture can be carried out, using steroid biosynthesis inhibitors and observing the effect of this hormone on ovarian activity of proteolytic enzymes in the follicular wall.

Liquid and Frozen Storage of Agouti (Dasyprocta leporina) Semen Extended with UHT Milk, Unpasteurized Coconut Water, and Pasteurized Coconut Water

This study evaluated the effects of semen extension and storage on forward progressive motility % (FPM%) in agouti semen. Three extenders were used; sterilized whole cow's milk (UHT Milk), unpasteurized (CW) and pasteurized coconut water (PCW), and diluted to 50, 100, 150, and 200 × 10⁶ spermatozoa/ml. Experiment 1: 200 ejaculates were extended for liquid storage at 5^∘C and evaluated every day for 5 days to determine FPM% and its rate of deterioration. Experiment 2: 150 ejaculates were extended for storage as frozen pellets in liquid nitrogen at −195^∘C, thawed at 30^∘ to 70^∘C for 20 to 50 seconds after 5 days and evaluated for FPM% and its rate of deterioration. Samples treated with UHT milk and storage at concentrations of 100 × 10⁶ spermatozoa/ml produced the highest means for FPM% and the slowest rates of deterioration during Experiment 1. During Experiment 2 samples thawed at 30^∘C for 20 seconds exhibited the highest means for FPM% (12.18 ± 1.33%), 85% rate of deterioration. However, samples were incompletely thawed. This was attributed to the diameter of the frozen pellets which was 1 cm. It was concluded that the liquid storage method was better for short term storage.

The gross and micro anatomy of the accessory sex glands of the male agouti (Dasyprocta leporina)

This study was a follow up to the study on the gross anatomy of the male agouti (Dasyprocta leporina) reproductive system. The seminal vesicles of the agouti are lobulated structures. The mean diameter of the large lumen is 883.6 +/- 76.83 microm. The mucosa (24.1 +/- 0.92 microm), which is lined by pseudo-stratified columnar epithelium is thrown into folds, which often branch. The lamina muscularis mucosa is thin and is made of loose connective tissue containing blood vessels. The mucosa of the leaf-like coagulating glands of the agouti is folded. The mean diameter of the lumen is 488.3 +/- 41.96 microm. The mucosa contains tubuloalveolar glands, which have a mean length of 199.5 +/- 28.83 microm. The thin epithelium, 15.0 +/- 1.25-microm wide, consists mostly of pseudo-stratified columnar cells. The epithelium also has surface modifications in the form of apical blebs and cilia. The epithelium of the agouti's lobulated prostate gland is also folded creating a large lumen with a mean diameter of 995.5 +/- 55.70 microm. The mucosa contains tubular and tubuloalveolar glands, each having a mean length of 134.4 +/- 13.59 microm. The epithelium (13.9 +/- 1.16 microm) consists of pseudo-stratified columnar cells. The pea-shaped bulbourethral gland (BG) of the agouti consists of convoluted tubular, mucous secretory units, which are irregularly shaped each with a mean length of 177.9 +/- 7.10 microm and a mean width of 63.5 +/- 3.97 microm. The BG of the agouti are ventro-lateral to the rectum and dorsally positioned to the pubic symphysis, and connected to the urethra by short ducts.

Spermatozoal morphologies and fructose and citric acid concentrations in agouti (Dasyprocta leporina) semen

This study was conducted to identify the levels of fructose and citric acid, and sperm morphologies in agouti (Dasyprocta leporina) semen. These parameters may be important in identifying highly fertile semen from the agouti. The objectives were: (1) to investigate spermatozoal abnormalities in agouti semen and (2) to determine the concentrations of seminal fructose and citric acid in agouti semen samples. Semen samples were collected from 16 anaesthetised male agouti by electro-ejaculation. Fructose and citric acid concentrations were 256.86+/-63.54 mg/dl and 1877+/-147 mg/dl, respectively, measured with ELISA kits. Sperm morphologies, examined using eosin-negrosin staining, showed 11 morphologies. The most abundant (68.5%) sperm morphology (M1) showed no known sperm defects. Means for head, mid piece, tail and total length of the agouti spermatozoa was 5.23+/-0.04 microm, 5.18+/-0.08 microm, 37.52+/-0.24 microm and 47.96+/-0.25 microm, respectively for M1 sperm. The means of spermatozoa head and mid piece width and semen volume were 3.26+/-0.04 microm, 0.70+/-0.02 microm and 0.47+/-0.16 ml, respectively. It was concluded that as the fructose concentration in agouti ejaculate increased the percentage of spermatozoa with known spermatozoa defects increased (r=0.506; P<0.037; n=32). It is suggested that the M1 sperm could be the most competitive spermatozoa in agouti ejaculate. In conclusion standards for identifying fertile agouti semen were established.

A preliminary technique for electro-ejaculation of agouti (Dasyprocta leporina)

This study focused on the effectiveness of electro-ejaculation of the agouti (Dasyprocta leporina) and analysis of the collected semen. Sexually mature male agouti were anesthetized with ketamine and electro-ejaculated. The means of ejaculation time was 5.48+/-0.31min, ejaculation voltage was 9.33+/-0.69V, ejaculation voltage range was 6-12V, amps was 0.5-1.5amps, ejaculation volume was 0.47+/-0.12ml and pH was 8.3+/-0.09. Mean spermatozoa concentration, motility and percentage abnormalities were (106.7+/-31.1)x10(6)spermatozoa/ml, 50.44+/-4.44%, and 35.14+/-2.76%, respectively. Thirty percent of the semen samples collected contained spermatozoa. The most significant result from these experiments was the inverse relationship between ejaculation time and ejaculate volume, which suggests that the maximum ejaculation time for electro-ejaculation of the agouti should not proceed beyond 6min. Secondly, the results indicate that the time of the off periods should be shortened to 3-4s.