Individual differences in behaviour and gut bacteria are associated in collared peccary (Mammalia, Tayassuidae).

AIMS: We tested the hypothesis that the behaviour of an individual is associated with the diversity of its gut bacteria, using the collared peccary (Pecari tajacu) as a model. METHODS AND RESULTS: In all, 24 adult male collared peccaries received either low- (n = 12) or high-fibre diet (n = 12) to induce contrasting gut fermentation profiles. They were submitted to three short-term challenges, allowing us to rate the animals in a coping-style dimension named 'calmness'. At the end of the experimental period, we collected samples of peccaries' forestomach contents to characterize bacterial diversity. We found a significant positive association between individual 'calmness' z-scores and the bacterial evenness index in gut bacteria (and a similar trend with the Simpson's diversity index), suggesting a more homogeneous bacterial community of calmer individuals. We also found a positive association between fibres digestibility and gut bacterial diversity in the peccaries' forestomach, but no effect of the dietary fibre level. CONCLUSIONS: Gut bacteria evenness increases with 'calmness' z-scores, suggesting a more homogeneous bacterial community of calmer individuals, compared with the more heterogeneous of the most distressed ones. Our results also suggest associations between the digestibility of ADF with the gut bacterial diversity indices and with the relative abundance of the Actinobacteria phylum. SIGNIFICANCE AND IMPACT OF THE STUDY: Our data showed that the hosts' individual behavioural differences are potentially aligned with gut bacterial diversity. The behaviour-microbiota link is correlated with host feed efficiency and, ultimately, may have implications for animal health and welfare of farm animals.

Individual differences in behavior affect total tract fiber digestibility: the example of collared peccary.

Differences in how individuals cope with stressful conditions (e.g. novel/unfamiliar environment, social isolation and increases in human contact) can explain the variability in data collection from nutrient digestibility trials. We used the collared peccary (Pecari tajacu), which is under process of domestication and shows high individual behavioral distinctiveness in reactions toward humans, to test the hypothesis that behavioral differences play a role in nutrient digestibility. We assessed the individual behavioral traits of 24 adult male collared peccaries using both the 'behavioral coding' and the 'subjective ratings' approaches. For the behavioral coding assessment, we recorded the hourly frequency of behaviors potentially indicative of stress during the 30-day habituation period to the experimental housing conditions. The subjective ratings were performed based on the individuals' reactions to three short-term challenge tests (novel environment, novel object and threat from a capture net) over a period of 56 days. During the last 26 days, the collared peccaries were fed diets either high (n = 12) or low (n = 12) in dietary fiber levels, and we determined the total tract apparent digestibility of nutrients. The individual subjective ratings showed consistency in the correlated measures of 'relaxedness', 'quietness' and 'satisfaction' across the three challenge tests, which were combined to produce z score ratings of one derived variable ('calmness'). Individual frequency of BPIS/h and calmness scores were negatively correlated and both predicted the total tract digestibility of acid detergent fiber (ADF), which ranged from 0.41 to 0.79. The greater the calmness z scores (i.e. calmer individuals), the greater the total tract digestibility of ADF. In contrast, the higher the frequency of BPIS/h, the lower the total tract digestibility of ADF. Therefore, our results provide evidence that by selecting calmer collared peccaries, there will be an increase in their capacity to digest dietary fiber.

The influence of urea feeding on the bacterial and archaeal community in the forestomach of collared peccary (Artiodactyla, Tayassuidae).

AIMS: This study was carried out to test whether bacterial and archaeal populations, and products of fermentation in each compartment of collared peccary stomach, vary significantly with urea feeding. Bacteria and archaeal population variation among the four stomach compartments were also compared. METHODS AND RESULTS: Archaeal and bacterial communities in the forestomach of four individuals per treatment - peccaries fed diets with and without urea - were analysed at molecular level using PCR followed by denaturing gradient gel electrophoresis. Volatile fatty acids profiles in the three different compartments of the forestomach were also compared. The bacterial community composition varied considerably among each compartment and with urea provision, but no variation was observed between archaeal populations. Differences in bacterial communities between treatments - with and without urea - were greater than amongst stomach compartments. The acetate: propionate proportion decreased with urea provision in diet. Some differences in bacterial but not archaeal community composition were observed in each compartment of the collared peccary forestomach. CONCLUSIONS: There are some differences in bacterial but not archaeal populations in each compartment of collared peccary stomach. Use of urea in the diet of peccary can substantially modify the profile of volatile fatty acids released in its forestomach, but does not influence the archaeal community composition. Urea has an important effect on bacterial population DGGE profile present in the peccary's forestomach. SIGNIFICANCE AND IMPACT OF THE STUDY: These results demonstrate the ability of the collared peccary to use urea as source of nonprotein nitrogen, and confirm a hypothesis that the collared peccary has a digestive physiology more similar to ruminant than nonruminant animals.

The effects of unrelated offspring whistle calls on capybaras (Hydrochoerus hydrochaeris).

Parent-offspring vocal communication, such as the isolation call, is one of the essential adaptations in mammals that adjust parental responsiveness. Thus, our aim was to test the hypothesis that the function of the capybara infants' whistle is to attract conspecifics. We designed a playback experiment to investigate the reaction of 20 adult capybaras (seven males and 13 females) to pups' whistle calls - recorded from unrelated offspring - or to bird song, as control. The adult capybaras promptly responded to playback of unrelated pup whistles, while ignoring the bird vocalisation. The adult capybaras took, on average, 2.6 ± 2.5 seconds (s) to show a response to the whistles, with no differences between males and females. However, females look longer (17.0 ± 12.9 s) than males (3.0 ± 7.2 s) toward the sound source when playing the pups' whistle playback. The females also tended to approach the playback source, while males showed just a momentary interruption of ongoing behaviour (feeding). Our results suggest that capybara pups' whistles function as the isolation call in this species, but gender influences the intensity of the response.

Análise da integridade funcional dos espermatozoides de Tayassu pecari por diferentes soluções hiposmóticas e osmolaridades / Analysis of the functional integrity of Tayassu pecari sperm by different hyposmotic solutions and osmolarities

Queixada (Tayassu pecari) é um mamífero neotropical, classificado como vulnerável devido à caça e à destruição de seu habitat. Em razão das dificuldades na reprodução em cativeiro, técnicas de reprodução assistida podem ser aplicadas em programas de repovoamento da espécie. Dessa forma, objetivou-se identificar o melhor protocolo de teste hiposmótico (HOST) para avaliar a integridade funcional dos espermatozoides de queixada. O sêmen de quatro machos adultos foi coletado com auxílio de eletroejaculador após contenção física e protocolo de sedação e anestesia. O sêmen foi avaliado quanto às características macro e microscópicas e diluído nas seguintes soluções hiposmóticas: água destilada (0mOsmol/L), sacarose (50, 100, 150mOsm/L) e frutose (50, 100, 150mOsm/L). Cada amostra foi incubada em duplicata, e uma sofreu fixação em solução de citrato de sódio formolizado a 4%. Duzentos espermatozoides foram avaliados por amostra e classificados em reativos ou não ao HOST. Todas as soluções testadas foram semelhantes em identificar o percentual de espermatozoides reativos, independentemente de a amostra ser ou não fixada (P>0,05). Dessa forma, pode-se usar água destilada como HOST por este apresentar resultados similares e por ser um teste mais barato.(AU)

White-lipped peccary (Tayassu pecari) is a neotropical mammal classified as vulnerable due to overhunting and habitat destruction. Due to the low reproduction success in captivity, assisted reproduction techniques can be used in re-stocking programs. Therefore, we aimed to identify the best hyposmotic swelling test (HOST) to evaluate the functional integrity of peccary sperm. Semen samples of four adult males were collected with the aid of an electroejaculator after physical contention, sedation and anesthesia protocols. The semen was evaluated for macro and microscopic characteristics and diluted in the following hyposmotic solutions: distilled water (0mOsmol/L), sucrose (50, 100, 150mOsm/L) and fructose (50, 100, 150mOsm/L). Each sample was incubated in duplicate and one was fixed in 4% formalized sodium citrate solution. Two hundred spermatozoa were evaluated from each sample and classified as reactive or not- reactive to HOST. There were similar proportions of reactive and functional sperm regardless of whether the sample was fixed or not fixed (P> 0.05). Therefore, distilled water can be used as HOST to evaluate the functional integrity of white-lipped peccary sperm because it shows similar results and it is a cheaper test.(AU)