Comparative Analysis of Maternal Colostrum and Colostrum Replacer Effects on Immunity, Growth, and Health of Japanese Black Calves.

Maternal colostrum (MC) is an important source of nutrients and immune factors for newborn calves. However, when colostrum is unavailable or of poor quality, a colostrum replacer (CR) may be a suitable alternative to MC. As stock-raising farmers must make informed decisions about colostrum feeding management, this study was conducted to determine the effect of feeding MC versus CR on the promotion of immunological status, growth, and health in pre-weaned Japanese black (JB) calves. Sixteen newborn JB calves were fed MC after birth, and 16 JB calves were fed CR. For the MC group, the numbers of γδ T cells, CD4+ cells, CD8+ cells, CD4+CD8+ cells, B cells, and MHC class II+ cells were significantly higher compared with the CR group. Furthermore, the expression levels of interleukin (IL)-1ß-, IL-2-, and interferon-γ (IFN-γ)-encoding mRNAs were significantly higher in the MC group compared with the CR group. A lower incidence of disease in 1-month-old calves and higher carcass weight in the MC group were observed compared with the CR group. These results suggest that CR activates the immune system delayed in calves compared with MC. MC increases populations of various immunocompetent cells, which can reduce infection rates and improve body weight gain.

Reproductive cycle and maturation of Swinhoe's tree lizard (Diploderma swinhonis (Günther, 1864)) in Hyuga City, Miyazaki Prefecture, Japan.

Swinhoe's tree lizard (Diploderma swinhonis) is an arboreal agamid that is native to Taiwan. The species has been introduced to some areas of Japan and is regarded as an invasive alien species. In 2016, a nonnative population of D. swinhonis was discovered in Hyuga City, Miyazaki Prefecture, Japan, but little information was available on the ecology of the population at the time. The main purpose of this study was therefore to investigate the reproductive cycle and maturation of this population. Field research was conducted from 2017 to 2019, and 764 lizards were collected. Euthanized lizards were dissected and the reproductive organs were examined to determine the reproductive period, clutch size, clutch frequency and size at sexual maturity. Females with oviductal eggs or vitellogenic ovarian follicles were observed from May to October. Clutch size ranged from 2 to 8, and clutch frequency was more than twice a year. In males, spermiogenesis started in early May and testicular regression was observed in September. Males with spermatozoa in the epididymides were found from May to November. Minimum snout-vent length at sexual maturity was 50.2 mm in females and 53.0 mm in males. Comparisons of the findings of this study and reports from Taiwan suggest that the nonnative population of D. swinhonis in Hyuga City has a higher fecundity than populations in Taiwan. It is therefore considered necessary to exterminate the population in Hyuga City before this species colonizes other areas.

Different doses of tannin reflect a double-edged impact on broiler chicken immunity.

Tannin is one of the most common phytochemical secondary phenolic metabolites, which is widely distributed in various plant production systems. Dietary intake of tannin can exert different actions on the immune system. The aim of this study was to evaluate the influence of different concentrations on broiler chicken immunity. Three groups (n = 10 in each group) were evaluated: control group given a normal basal diet, high tannic acid (HT) group given high-dose tannic acid (30 g/kg diet) and low tannic acid (LT) group given low-dose tannic acid (0.5 g/kg diet) for 35 days. Feed intake and body weight were measured weekly. Cells were isolated from thymus, spleen and caecal tonsils at the end of the study. Lymphocyte subsets, monocytes phagocytosis and cytokine mRNA expression in spleen were evaluated. The results showed that HT group chickens had decreased daily gain, final body weight, daily feed intake and relative weights of lymphoid organs compared with other groups. In thymus, spleen and caecal tonsils, relative CD4+, CD8+, CD4+CD8+ and γδ+ cell populations in the HT group were significant decreased in comparison with those of other groups. The relative B cell population in the HT group was also significant decreased. Cytokine mRNA expression in spleen cells of the HT group was also significantly lower than that in other groups. Conversely, CD4+CD8+ subpopulations in spleen and caecal tonsils, γδ+ cells in spleen and B cells in caecal tonsils of the LT group were significantly higher than those of the control group. In addition, IFN-γ mRNA expression in the LT group was significantly higher than that of the control group. These results demonstrated that dietary intake of tannin had positive and negative effects on broiler chicken immunity in a dose-dependent manner.