Zoo Biology

The potential of assessing adrenal responses to psychological stressors through the radioimmunoassay of free cortisol in urine was examined in the domestic cat (Felis catus) and in three nondomestic felid species (Felis geoffroyi, Felis bengalensis, and Felis concolor). To determine the approximate clearance rate of an acute increase in glucocorticoid secretion, serial plasma and bladder urine samples were collected from eight domestic cats after a 0.125 mg adrenocorticotropic hormone (ACTH) challenge. Within 30 min of administration, mean serum cortisol concentrations increased tenfold. Urinary cortisol concentrations increased twofold by 2 hr post‐ACTH and were correlated with the serum responses. Also, 16 domestic cats were anesthetized, injected with 0.125 mg ACTH, and serially bled for 3 hr. All urine was collected for 24 hr post‐ACTH. Urinary cortisol concentrations were significantly elevated compared to pretreatment concentrations and were correlated to the serum cortisol response (net area under the response curve). In another experiment, urine was collected daily for a 7‐day baseline period from 16 domestic cats housed in standard laboratory cages. Subsequently, 8 cats were subjected to 8 consecutive days of “stress,” consisting of relocation, physical restraint, and jugular venipuncture. The other 8 cats were‐neither moved, nor handled, nor bled for the same period of time. Two patterns of response were observed among the “stressed” cats: urinary cortisol concentrations either increased or decreased between baseline and treatment periods. These response profiles differed from those of controls, which remained basal and unchanged over time. A fourth experiment involved relocating a female Geoffroy's cat, 4 leopard cats, and 2 pumas to a novel environment for 8–10 days. Urinary cortisol concentrations rose on the first day of relocation and remained elevated above baseline for 5–7 days. Overall, these data suggest that adrenal responsiveness to psychological stressors in these four felid species can be assessed noninvasively by measuring coritsol in 24‐hr urine samples. This research strategy may be useful for optimizing captive habitats to improve overall animal welfare and/or reproductive performance. © 1992 Wiley‐Liss, Inc.

We trialled the efficacy of various exogenous hormones to induce spermiation, courtship behavior, and spawning in the “endangered” southern bell frog, Litoria raniformis. Intralymphatic administration of Lucrin^®, a synthetic nonapeptide luteinizing hormone releasing hormone (LHRH), was used successfully to induce courting behaviors and ejaculation of spermatozoa in males. Various hormones, including Lucrin^®, another synthetic LHRH analog ([des‐Gly¹⁰, D‐Ala⁶]‐LHRH), human chorionic gonadotropin, progesterone, and a dopamine receptor antagonist failed to promote oviposition and spawning in females. This and earlier studies indicate that in the efficacy of hormonal induction in amphibians varies between taxa, hormones, and genders. The lack of response in females may limit the use of reproduction technology in the southern bell frog and closely related species of Australian bell frogs. Zoo Biol 29:774–782, 2010. © 2010 Wiley‐Liss, Inc.

Attempts to improve animal welfare have commonly centered around three broad objectives: (1) to ensure good physical health and functioning of animals, (2) to minimize unpleasant “affective states” (pain, fear, etc.) and to allow animals normal pleasures, and (3) to allow animals to develop and live in ways that are natural for the species. Each of these objectives has given rise to scientific approaches for assessing animal welfare. An emphasis on health and functioning has led to assessment methods based on rates of disease, injury, mortality, and reproductive success. An emphasis on affective states has led to assessment methods based on indicators of pain, fear, distress, frustration and similar experiences. An emphasis on natural living has led to research on the natural behavior of animals and on the strength of animals' motivation to perform different elements of their behavior. All three approaches have yielded practical ways to improve animal welfare, and the three objectives are often correlated. However, under captive conditions, where the evolved adaptations of animals may not match the challenges of their current circumstances, the single‐minded pursuit of any one criterion may lead to poor welfare as judged by the others. Furthermore, the three objectives arise from different philosophical views about what constitutes a good life—an area of disagreement that is deeply embedded in Western culture and that is not resolved by scientific research. If efforts to improve animal welfare are to achieve widespread acceptance, they need to strike a balance among the different animal welfare objectives. Zoo Biol 28:507–518, 2009. © 2009 Wiley‐Liss, Inc.

Reproductive endocrine patterns were characterized in female ocelots (Leopardus pardalis; n = 3), tigrinas (Leopardus tigrinus; n = 2), and margays (Leopardus wiedii; n = 2) housed in captivity in southern Brazil. Females were maintained as singletons and exposed to natural fluctuations in photoperiod. Cyclic changes in ovarian steroids were monitored by analyzing estrogen and progestogen metabolites in fecal samples collected five times weekly for 14 to 18 months. Based on intervals between fecal estrogen peaks, mean (± SEM) duration of the estrous cycle was 18.4 ± 1.6 days for the ocelots (range, 7–31 days; n = 75 cycles), 16.7 ± 1.3 days for the tigrinas (range, 11–27 days; n = 23 cycles), and 17.6 ± 1.5 days for the margays (range, 11–25 days; n = 32 cycles). Fecal progestogen analyses combined with two laparoscopic observations of the ovaries confirmed that ocelots and tigrinas did not ovulate spontaneously. In contrast, non‐mating–induced luteal phases of 40.1 ± 6.3 days in duration (range, 30–60 days) were observed frequently in both margays. There was no evidence of gonadal seasonality in margays in either follicular or luteal activity. In ocelots, cyclic changes in estrogen excretion were observed during each month of the year; however, only one female cycled continuously. In the other two ocelots, periods of acyclicity of several months’ duration were observed. It was not possible to conclude whether tigrinas were aseasonal because estrous cyclicity was observed in only one of two individuals. In the female that cycled, a 3‐month period of acyclicity was observed in the late fall/early winter. These data demonstrate similarities among three felid species of the genus Leopardus, including evidence they are polyestrous but experience unexplained periods of ovarian inactivity. Only the margays differed by exhibiting occasional spontaneous, non‐mating–induced ovulations. Historically, these species have not bred well in captivity. However, it is hoped that understanding the biological similarities and differences among them could lead to improved management strategies that may one day result in increased reproductive success. Zoo Biol 20:103–116, 2001. © 2001 Wiley‐Liss, Inc.

Reproductive evaluations were conducted on 185 male cats representing eight endemic Latin American species that were maintained in 44 zoos and private facilities in 12 Latin American countries. Reproductive assessments (testicular measures, ejaculate quality, and blood testosterone/cortisol concentration) were used to establish normative values for large‐ and small‐sized cats in Latin American collections. Data also were analyzed using multiple regression to study the impact of proven breeder status, diet, and various animal housing combinations. Most felids (>95%) in the survey were of wild‐born origin, and <20% had produced offspring in captivity. Larger felids had bigger testes and produced more semen, but tended to produce low‐sperm‐density ejaculates. The ejaculates of small felids were more sperm‐concentrated, but contained fewer total spermatozoa. Sperm motility was unrelated to species size, and certain species (puma, margay, tigrina, and jaguarundi) consistently produced few (<40%) normal sperm forms. Across species, >50% of males had low sperm counts (<1 million total sperm per ejaculate). Among large cats (jaguars and pumas), proven breeders had larger (P<0.05) testes, greater semen volume, and more normal sperm than nonbreeders. Males on adequate diets had higher (P<0.05) circulating cortisol. Among small‐sized felids, proven breeders had higher (P<0.05) testosterone, and males housed alone or paired with a conspecific female had more (P<0.05) total sperm per ejaculate and greater (P<0.05) seminal and testicular volumes. Fifty‐nine ejaculates (potentially representing ∼100 artificial insemination (AI) or 26,000 in vitro fertilization (IVF) procedures) were cryopreserved for a felid genome resource bank. In conclusion, breeding success and reproductive traits for many endemic felids in Latin American zoos appear to be suboptimal, and likely would benefit from improvements in diet and exhibitry. Technology transfer and continued training of zoo staff and scientists in Latin American countries are essential if these zoos are to achieve their tremendous conservation potential for felids and other threatened endemic species. Zoo Biol 22:421–441, 2003. © 2003 Wiley‐Liss, Inc.

Fecal samples were collected for 14–26 months from three male and six female Pallas' cats (Otocolobus manul) to examine gonadal steroidogenic activity in response to changes in photoperiod and treatment with exogenous gonadotropins. Females exhibited a seasonal anestrus from May–December, excreting consistently low concentrations of fecal estrogens (overall mean, 50.2±8.5 ng/g). During the breeding season (January–April), baseline fecal estrogen concentrations were higher, averaging 128.4±18.9 ng/g, with peak concentrations ranging from 455.8–909.6 ng/g. Interpeak intervals in estrogen excretion ranged between 7 and 21 days, with an average estrous cycle length of 14.3±1.7 days. Two females became pregnant after natural mating, with overall luteal progestogen concentrations averaging ∼40 μg/g throughout gestation. Fecal estrogens increased in mid‐gestation, peaking just before birth. Induction of follicular development with eCG (100–300 IU, i.m.) resulted in an increase in fecal estrogens (peak range, 263.1–1198.1 ng/g), followed by a postovulatory increase in fecal progestogens (overall mean, 41.1±11.9 μg/g) after hCG (75–150 IU, i.m.). Despite apparently normal ovarian responses, none of the females conceived after artificial insemination (AI). The gonadotropin‐induced nonpregnant luteal phase lasted 49.8±5.3 days (range, 30–60 days), whereas gestation lasted ∼70 days. In the male Pallas' cat, fecal androgens were elevated from November–April (overall mean, 352.3±30.3 ng/g) compared with nadir concentrations during the rest of the year (82.1±3.3 ng/g). Entrainment of seasonality to photoperiod was demonstrated by stimulation of gonadal steroidogenic activity in cats exposed to increasing artificial light during natural (nonbreeding season) and artificially induced short‐day photoperiods. In summary, reproduction in Pallas' cats is highly seasonal and photoperiod‐dependent. Females exhibit elevated baseline and peak fecal estrogen concentrations for 3–4 months during late winter/early spring. Testicular steroidogenic activity precedes the rise in female estrogen excretion by about 2 months, presumably to ensure maximal sperm production during the breeding season. Zoo Biol 21:347–364, 2002. Published 2002 Wiley‐Liss, Inc.

Ovarian activity in the female giraffe was evaluated during the nonfertile ovarian cycle and during the terminal stages of gestation. Progesterone metabolites, in the form of pregnanediol‐3‐glucuronide (PdG), were measured in daily random urine samples collected from four adult parous giraffes. The follicular phase averaged 4.0 ± 0.1 days in length (N = 12; range 3–5 days) and peak PdG levels in the postovulatory period averaged 30.9 ± 1.7 ng/mg Cr (N = 12). PdG levels during the latter half of gestation greatly exceeded average luteal phase levels, which is in contrast to domestic ruminants. Prior to parturition, a marked decline in PdG excretion was evident, which may be useful for anticipating this event. These data serve to elucidate ovarian function in the mature female giraffe and to provide information concerning the physiologic role of certain anomalous ovarian structures. In addition, observed similarities in the pattern of PdG excretion during the nonfertile cycles of the giraffe and the okapi indicate similar underlying physiologic processes.

Coadaptation can occur either because of local adaptation in a geographically widespread population and/or because of intrinsic adaptation to the state of other genes or chomosomes. In either event, hybridization between animals with differently coadapted gene or chromosomal complexes can result in a decrease in fertility, viability, etc. in the initial hybrids and especially in later generations. This is known as an outbreeding depression. Moreover, releasing animals not adapted to the local environment can seriously hamper the effectiveness of a reintroduction program, and hybridization can also destroy the local adaptation. Coadapted gene complexes are best detected through studies on natural populations because the adaptive nature of the complex is often only apparent in the natural environment. In the absence of information on natural populations (but ideally as a supplement), the presence of coadapted gene complexes and population boundaries can be detected through mating behavior, a pedigree analysis that can detect outbreeding depressions and distinguish them from inbreeding depressions, or genetic and karyotypic surveys. Once an outbreeding depression has been detected, it can be used to redefine the boundaries of the populations to be managed. Basically, the outbreeding depression is avoided by preventing hybridization between animals with the different coadapted complexes. In some cases, formal subspecific designations have been used to define the population boundaries. Unfortunately, many subspecific designations were made before population‐thinking influenced taxonomy. It is important to emphasize the need to undertake modern biological studies and to collect additional information useful for systematics. If modern biological studies indicate that the subspecies have little or no biological significance, it is best to treat the animals as a single population and disregard the subspecific designations.

A variety of invertebrates are commonly fed to insectivorous animals by both zoos and hobbyists, but information as to the nutrient composition of most commercially raised species is limited. Adult house crickets, house cricket nymphs (Acheta domesticus), superworms (Zophobas morio larvae), giant mealworm larvae, mealworm larvae and adult mealworms (Tenebrio molitor), waxworm larvae (Galleria mellonella), and silkworm larvae (Bombyx mori) were analyzed for moisture, crude protein, crude fat, ash, acid detergent fiber (ADF), neutral detergent fiber (NDF), minerals, amino acids, fatty acids, and vitamins. Earthworms (Lumbricus terresstris) were analyzed for moisture, crude protein, crude fat, ash, ADF, NDF, minerals, amino acids, and vitamins A and D₃. Proximate analyses were variable, with wide ranges found for moisture (57.9–83.6%), crude protein (9.3–23.7%), crude fat (1.6–24.9%), ADF (0.1–7.4%), NDF (0.0–11.5%), and ash (0.6–1.2%). Energy content ranged from a low of 674 kcal/kg for silkworms to 2,741 kcal/kg for waxworms.Using an amino acid scoring pattern for rats, the first limiting amino acid for all invertebrates tested was the total sulfur amino acid methionine+cystine. Deficiencies by nutrient (% of samples deficient vs. NRC requirements for rats on a dry matter (DM) basis) were as follows: calcium (100%), vitamin D₃ (100%), vitamin A (89%), vitamin B₁₂ (75%), thiamin (63%), vitamin E (50%), iodine (44%), manganese (22%), methionine‐cystine (22%), and sodium (11%). Deficiencies by invertebrate species (number of nutrients deficient vs. the NRC requirements for rats on a DM basis) were as follows: waxworms (9), superworms (8), giant mealworm larvae (7), adult mealworms (6), mealworm larvae (5), adult house crickets (4), house cricket nymphs (4), silkworms (4), and earthworms (4). These data provide a basis for determining nutrient intake of captive insectivores, and will aid in the development of gut‐loading diets to provide captive insectivorous animals with appropriate levels of necessary nutrients. Zoo Biol 21:269–285, 2002. © 2002 Wiley‐Liss, Inc.