A training program for noninvasive semen collection in captive western lowland gorillas (Gorilla gorilla gorilla)

Assisted reproductive technologies for endangered species conservation: developing sophisticated protocols with limited access to animals with unique reproductive mechanisms

Assisted reproductive technologies (ARTs) have been proposed as a means of overcoming the significant challenges of managing small, isolated populations of endangered species in zoos. However, efficient protocols for ARTs do not exist for most endangered species. This review will focus on research efforts to characterize unique reproductive mechanisms and develop species-specific ARTs. Central to these studies are assays to measure steroid metabolites in urine or feces and/or training programs to allow unrestrained blood collections and ultrasound evaluations. The resulting information about estrous cycle dynamics, combined with studies of semen collection and processing, provides the foundation for the development of artificial insemination (AI). In vitro fertilization and embryo transfer are also discussed in relation to the advantages these techniques could provide relative to AI, as well as the significant challenges involved with technologies that require oocytes and embryos. Finally, an argument is made for additional research of nontraditional model species (e.g., domestic cats and dogs) and the development of novel models representing unique taxa. Whether these species are studied by zoo-based researchers with the expressed intent of developing ARTs for conservation or academic scientists interested in basic biology, the resulting information will provide a unique, evolutionary perspective on reproduction that could have wide-reaching benefits. The more information we have available, the better our chances will be of developing effective ARTs and making a difference in conservation efforts for endangered species.

An Examination of Shaping with an African Crested Porcupine (Hystrix cristata)

Shaping through differential reinforcement of successive approximations to a target response has been a cornerstone procedure for the training of novel behavior. However, much of how it has traditionally been implemented occurs through informal observation, rather than any direct, systematic measurement. In the following study, an African crested porcupine (Hystrix cristata) was trained to touch and hold to a target for 30 s. A changing-criterion design with one reversal was used to assess the success of the shaping procedure and empirically examine the effects of the shaping procedure during each step of the program. The study allowed for the examination of each approximation across all other approximations, as well as across aberrant (e.g., trial-terminating) responses. The design and procedure allow for a simple and systematic way to examine the effects and success of shaping procedures across a variety of settings, species, and purposes.

Orangutans' Comprehension of Zoo Keepers' Communicative Signals

Zoological institutions often encourage cooperative interactions between keepers and animals so as to promote animals' welfare. One useful technique has been conditioning training, whereby animals learn to respond to keepers' requests, which facilitates a number of, otherwise sensitive, daily routines. As various media have been used to convey keepers' instructions, the question remains of which modality is best to promote mutual understanding. Here, we explored this question with two captive female orangutans. In the first experiment, we compared orangutans' understanding of previously acquired instructions when those were performed with verbal signals only, gazes only, gestures only, and when all those modalities were combined. Our results showed that gestures were sufficient for successful comprehension by these two apes. In the second experiment, we asked whether this preference could be driven by the non-arbitrary relationship that gestures bear to what they refer to, through iconicity or pointing. Our results revealed that neither iconicity nor pointing helped the subjects comprehend the keepers' instructions. Our results indicate a preference for instructions given through gestural signals in two captive female orangutans, although its cause remains elusive. Future practice may encourage the use of gestures in communication between keepers and orangutans in general or potentially other animals.

Cryopreservation of lar gibbon semen collected by manual stimulation

We confirmed ejaculation as a result of manual stimulation in a lar gibbon, and attempted to cryopreserve the semen using TES-Tris-egg yolk-based (TTE) extender. After measuring the amount of semen (g), we first diluted the semen with TTE extender, and calculated sperm concentration (sperm/ml), total sperm count (sperm), and progressive sperm motility (%). Then, we cooled diluted semen slowly to 4 °C over 2 h, and added an equal volume of secondary extender containing glycerol over 30 min. Finally, we flash-froze the semen solution by plunging into liquid nitrogen. In addition, we freeze-thawed the solution to determine the recovery rate of the motile sperm. Collection of semen was successful on four of the five occasions. The median (min-max) quantity of ejaculate was 0.19 g (0.09-0.26 g), the median sperm concentration was 1.38 × 10(9) sperm/ml (1.20-1.53 × 10(9) sperm/ml), and the median total sperm count was 0.26 × 10(9) sperm (0.11-0.40 × 10(9) sperm). Moreover, the median sperm motility immediately after ejaculation was 65 % (60-75 %), the median sperm motility after freeze-thawing was 30 % (25-35 %), and the median recovery rate was 42.3 % (40.0-58.3 %). We were able to (1) collect semen from a lar gibbon by manual stimulation, (2) reveal andrological findings regarding semen characteristics, and (3) preserve the genetic resource using TTE cryopreservation.

Testing the effect of medical positive reinforcement training on salivary cortisol levels in bonobos and orangutans

The management of captive animals has been improved by the establishment of positive reinforcement training as a tool to facilitate interactions between caretakers and animals. In great apes, positive reinforcement training has also been used to train individuals to participate in simple medical procedures to monitor physical health. One aim of positive reinforcement training is to establish a relaxed atmosphere for situations that, without training, might be very stressful. This is especially true for simple medical procedures that can require animals to engage in behaviours that are unusual or use unfamiliar medical devices that can be upsetting. Therefore, one cannot exclude the possibility that the training itself is a source of stress. In this study, we explored the effects of medical positive reinforcement training on salivary cortisol in two groups of captive ape species, orangutans and bonobos, which were familiar to this procedure. Furthermore, we successfully biologically validated the salivary cortisol assay, which had already been validated for bonobos, for orangutans. For the biological validation, we found that cortisol levels in orangutan saliva collected during baseline conditions were lower than in samples collected during three periods that were potentially stressful for the animals. However, we did not find significant changes in salivary cortisol during medical positive reinforcement training for either bonobos or orangutans. Therefore, for bonobos and orangutans with previous exposure to medical PRT, the procedure is not stressful. Thus, medical PRT provides a helpful tool for the captive management of the two species.

Effect of positive reinforcement training on physiological and behavioural stress responses in the hamadryas baboon (Papio hamadryas)

Behavioural and salivary Cortisol responses were measured in hamadryas baboons (Papio hamadryas) (n = 5) undergoing positive reinforcement training (PRT). Compliance was assessed by collecting behavioural data on desirable and undesirable responses during each training session (33-46 training sessions per male). Saliva was collected before implementation of the training programme (3-4 baseline samples per male) and immediately before and ten minutes after a training session (24-53 saliva samples per male). During training, the incidence of leaving the training area, vocalising and threat displays changed across time. Performance of the desired behaviour (holding a target for increasing increments of time) improved for all males during the study period. Concentrations of salivary cortisol were similar for pre-training and post-training collection times, but both were significantly lower than baseline concentrations. The overall decline in undesirable behaviours and the absence of constantly elevated salivary cortisol suggest that PRT had no adverse effects on animal welfare.

Resting heart rate and tympanic temperature in operant conditioned western lowland gorillas (Gorilla gorilla gorilla)

The conscious, resting heart rate and body temperature of healthy western lowland gorillas (Gorilla gorilla gorilla) is not reported in the literature. To obtain this information, two clinically healthy adult male western lowland gorillas in a training program were conditioned to allow auscultation and obtain tympanic temperatures. The mean heart rate was 73.8 +/- 8.96 beats per minute (n = 176), and it was lower than mean heart rate reported in studies on anesthetized gorillas. The mean tympanic temperature was 35.5 +/- 0.7 degrees C (95.9 +/- 1.23 degrees F) (n = 209). The right tympanic temperature (rtt) and left tympanic temperature (ltt) were recorded separately for one gorilla. A small but statistically significant difference was present between the mean rtt of 35.8 +/- 0.7 degrees C (96.5 +/- 1.2 degrees F) (n = 137) and the mean ltt of 35.7 +/- 0.8 degrees C (96.2 +/- 1.3 degrees F) (n = 121).

Flow Cytometric Sorting of Fresh and Frozen-Thawed Spermatozoa in the Western Lowland Gorilla (Gorilla gorilla gorilla)

We adapted flow cytometry technology for high-purity sorting of X chromosome-bearing spermatozoa in the western lowland gorilla (Gorilla gorilla gorilla). Our objectives were to develop methodologies for liquid storage of semen prior to sorting, sorting of liquid-stored and frozen-thawed spermatozoa, and assessment of sorting accuracy. In study 1, the in vitro sperm characteristics of gorilla ejaculates from one male were unchanged (P > 0.05) after 8 hr of liquid storage at 15 degrees C in a non-egg yolk diluent (HEPES-buffered modified Tyrode's medium). In study 2, we examined the efficacy of sorting fresh and frozen-thawed spermatozoa using human spermatozoa as a model for gorilla spermatozoa. Ejaculates from one male were split into fresh and frozen aliquots. X-enriched samples derived from both fresh and frozen-thawed human semen were of high purity, as determined by fluorescence in situ hybridization (FISH; 90.7%+/-2.3%, overall), and contained a high proportion of morphologically normal spermatozoa (86.0%+/-1.0%, overall). In study 3, we processed liquid-stored semen from two gorillas for sorting using a modification of methods for human spermatozoa. The sort rate for enrichment of X-bearing spermatozoa was 7.3+/-2.5 spermatozoa per second. The X-enriched samples were of high purity (single-sperm PCR: 83.7%) and normal morphology (79.0%+/-3.9%). In study 4 we examined frozen-thawed gorilla semen, and the sort rate (8.3+/-2.9 X-bearing sperm/sec), purity (89.7%), and normal morphology (81.4%+/-3.4%) were comparable to those of liquid-stored semen. Depending on the male and the type of sample used (fresh or frozen-thawed), 0.8-2.2% of gorilla spermatozoa in the processed ejaculate were present in the X-enriched sample. These results demonstrate that fresh or frozen-thawed gorilla spermatozoa can be flow cytometrically sorted into samples enriched for X-bearing spermatozoa.

Benefits of positive human interaction for socially housed chimpanzees

Human interaction as environmental enrichment for chimpanzees (Pan troglodytes) and other primates is widely promoted and believed to be of value, but has been subject to little objective evaluation. This study assessed the effects of positive human interaction (eg relaxed treat feeding, playing, and other forms of social interaction compatible with personnel safety) on the behaviour of adult chimpanzees. Subjects were housed indoors in groups of two or three individuals. The level of interaction during routine care and management (ie in the process of cleaning, feeding, and monitoring) represented the baseline condition. The test condition involved a familiar caretaker spending an additional 10 mins per day, 5 days a week, with each chimpanzee. This study was designed to assess carry-over effects of interaction on behaviour outside the context of care staff presence. Therefore, in all phases of the study, data (97 h of focal animal sampling) were collected only when caretakers were absent from the building. During the increased human interaction phase, the chimpanzees groomed each other more and showed lower levels of the following behaviours: regurgitation/reingestion, other oral abnormal behaviours, inactivity, and reactivity to the displays of neighbouring groups. A trend towards reduced agonistic display was also detected. Attempted interactions with the observer shifted significantly from predominantly aggressive to predominantly affiliative in nature. These results suggest that simple, unstructured affiliation between humans and chimpanzees should be a valued component of behavioural management.

In vitro manipulation of nonhuman primate gametes for embryo production and embryo transfer

Since nonhuman primates are closely related to humans and share many physical similarities, they are important for use in research areas such as human infectious diseases, reproduction, physiology, endocrinology, metabolism, neurology and longevity. To develop and maintain these animals, we must establish techniques for in vitro manipulation of spermatozoa and eggs. For a decade my research group has been conducting basic research to establish embryo manipulation techniques and to clarify the reproductive phenomena in nonhuman primates. This article summarizes the past research on in vitro manipulation of nonhuman primate gametes, from collection of reproductive cells and in vitro fertilization to the birth of offspring after embryo transfer, as well as the current status of these research areas. The studies summarized here will directly lead to the development of standard techniques for practical and comprehensive use in nonhuman primates.