Animals

The adaptation strategies of species to local environments are reflected in phenotypic variations, which could be expressed as trait patterns across the community level. Here, we compiled a dataset of small mammal traits to evaluate the classic ecological rules and to assess predictions related to drought resistance. In June 2017, July 2023, and May–June 2024, a field survey was conducted in Baima Snow Mountain, southwest China, using standardized methods to capture small mammals. Traits potentially corresponding to variations in temperature, productivity, and water availability were measured in the field or calculated in the laboratory. We applied ordinary least squares (OLS) linear regressions to determine the community-level trait variations along the gradients of environmental factors influenced by rain-shadow effects of the mountain system. Results showed that (1) body size decreased with increasing temperature, aligning well with conventional prediction; (2) the proportion of appendage size attributable to allometry decreased with temperature but increased slightly with productivity, thereby violating Allen’s rule while being partly consistent with the resource rule; (3) the renal features did not support the expected negative association concerning water availability but its converse, which may be explained by microhabitat conditions and broad-scale zoogeographic influences within the local community. We conclude that community-level phenotypic variations in small mammals result from complex influences, including climate, productivity, habitat characteristics, and adaptive strategies operating at both micro and macro scales.

Currently, there are limited reports on prediction models of standardized ileal amino acid digestibilities (SIAADs) in soybean meals (SBMs) for medium-growing yellow-feathered chickens. This study firstly analyzed the chemical compositions of 10 SBMs, then determined their SIAADs in chickens, and finally established and verified prediction models for SBM SIAADs based on their chemical compositions and amino acid (AA) profiles. A total of 276 55 d-old Tianluma roosters were selected and randomly divided by body weight into 11 treatment groups. On d 63, chickens were fed either a nitrogen-free diet (NFD) or one of 10 SBM diets for 5 d. On d 67, ileal chyme samples were collected to determine SIAADs. Data from nine SBM samples and stepwise regressions were employed to build prediction models, while one SBM sample was randomly selected to validate model accuracy. Different SBM sources affected (p ≤ 0.007) SIAADs in medium-growing yellow-feathered chickens. The standardized ileal digestibility (SID) of glutamic acid (Glu) was the highest (93.9%), whereas that of cysteine (Cys) was the lowest (81.7%). Fifteen prediction models (R² = 0.567–0.993, p < 0.03) for the SIDs of methionine (Met), isoleucine (Ile), leucine (Leu), phenylalanine (Phe), lysine (Lys), histidine (His), arginine (Arg), aspartic acid (Asp), serine (Ser), Glu, glycine (Gly), alanine (Ala), Cys, tyrosine (Tyr), and proline (Pro) in SBMs for medium-growing yellow-feathered chickens were effectively established based on chemical compositions and AA profiles. Among them, the prediction model for the SID of Cys showed the best fit (R² = 0.993, p = 0.002), while the model for the SID of Ala had the lowest fit (R² = 0.567, p = 0.019). Except for His and Pro, which exhibited poor predictive accuracy, all other models showed good accuracy. These prediction models thus provide a valuable reference for rapidly estimating the SIDs of key AAs in SBMs for medium-growing yellow-feathered chickens.

Weaning is one of the most stressful stages in pig production, especially for Iberian piglets, which grow more slowly than other cosmopolitan breeds and therefore, have a lower weaning weight when raised in intensive systems. Stress at weaning, caused by separation from the sow, dietary change, and regrouping with unfamiliar piglets, can negatively impact welfare, immune function, and performance. Pre-weaning socialization, which allows piglets from different litters to interact before weaning, has been proposed as a strategy to reduce aggression and facilitate the adaptation to the post-weaning period. However, its physiological effects in Iberian pigs remain largely unknown. In this study, 8 Iberian sows and their litters were assigned to either a control group (CTRL) or a socialization group (SOC) where litters were mingled (socialized) two weeks before weaning. Salivary and serum biomarkers of stress, inflammation, immunity and metabolism were measured at weaning (pwD0) and 7 days post-weaning (pwD7), and growth performance was recorded until 60 days of age. Socialized piglets showed reduced salivary Adenosine Deaminase (ADA) activity at pwD0 and pwD7 and lower salivary chromogranin A (CgA) and serum Haptoglobin (Hp) levels at pwD7. In contrast, they presented higher concentrations in serum of high-density lipoprotein (HDL), low-density lipoprotein (LDL), total cholesterol, glucose, and urea at pwD7 compared to controls. Attending to the sex effect, Butyryl-cholinesterase (BChE) serum concentration was higher in males and urea, and creatinine were higher in females. Growth rates were higher in socialized piglets in the first two weeks post-weaning but lower thereafter. These findings may suggest that pre-weaning socialization could reduce the stress associated with early post-weaning in Iberian piglets, thus potentially improving welfare and adaptation during this period.