Ram-induced oestrus and ovulation in lactating and weaned Corriedale ewes

Two experiments were conducted in consecutive years in which recently (Experiment 1) or temporarily (Experiment 2) weaned ewes and matched post-partum non-lactating flockmates (DRY) were exposed to a stimulus group of rams and oestrous ewes (10 and 20 in Experiment 1, 20 and 20 in Experiment 2) for 28 days in spring. Lactating ewes (n = 130) in Experiment 1 were isolated from their lambs 4 (W-4), 2 (W-2), 1 (W-1) or 0 (W-0) days in advance and exposed along with a group of 32 DRY flockmates. Lactating ewes in Experiment 2 (n = 230) were allocated to an unreplicated factorial of two levels of temporary weaning before stimulation (B0: control; B24: lambs removed 24 h before stimulation) by four levels of ewe-lamb contact imposed at the start of the stimulation (A0: control; A12, A24 and A36: lamb-ewe separation during the initial 12, 24 or 36 h of exposure); DRY ewes (n = 54) acted as an augmented factorial control. Oestrus (rump marks) and ovulation (laparoscopy on day 5 and on day 28 (Experiment 1) or day 32 (Experiment 2)) were recorded. Ovulation and oestrous responses in Experiment 1 were similar for DRY (90.6% and 55.2%, respectively) and recently weaned ewes (83.8% and 53.7%, respectively). Amongst recently weaned ewes, the immediate ovulation response to the rams and the proportion of ewes still cycling by day 28 tended to be lower (P = 0.065 and P = 0.011) in ewes weaned on the day of ram exposure (71.9% and 54.8% v. 87.8% and 80.0%, respectively). Ovulation rate was lower (P < 0.003) in W-2 ewes (1.3 ± 0.10) than in the other recently weaned groups. In Experiment 2, ovulation (83.3%) and oestrous (68.9%) responses in DRY ewes were higher (P = 0.022 and P = 0.053, respectively) than in lactating ewes (66.2% and 51.0%, respectively). More ewes ovulated (P = 0.036) in B24 (70.5%) than in B0 (61.8%). Ewes having their lambs returned 12 h after the onset of stimulation (A12) had poorer ovulation responses (54.9%) than control ewes (A0, 72.9%, P < 0.05); this was probably associated to lamb restitution after the sunset. Main conclusions were that (i) the presence of the lambs is a depressing factor of both ovulation and oestrous responses to the ram effect in lactating ewes, (ii) the ovulation response of lactating ewes will probably benefit from removing lambs for a period of 24 h before the onset of stimulation, (iii) until additional information becomes available, temporary weaning protocols should be designed avoiding lamb restitution during the night.     

Maternal chitosan oligosaccharide supplementation affecting expression of circadian clock genes,and possible association with hepatic cholesterol accumulation in suckling piglets

Chitosan oligosaccharide (COS) has been shown to reduce lipid accumulation in liver in mice and rats. The purpose of this study was to investigate whether maternal COS feeding affects hepatic lipid metabolism via influencing the expression of circadian clock genes in piglets. From day (d) 85 of gestation to d 14 of lactation, sixteen pregnant sows were divided into a control group (basal diet without COS supplementation) and a COS group (30 mg COS/kg basal diet). After farrowing, one piglet per litter in each group was selected for the collection of plasma and liver samples on d 0 and d 14 of age, respectively. Interestingly and significantly, we found that maternal COS supplementation promoted plasma and hepatic cholesterol accumulation and up-regulated the mRNA level of negative-regulated element period 1 (Per1), and reduced the abundance of the positive elements, circadian locomotor output cycles kaput (CLOCK), and brain muscle Arnt-like 1 (BMAL1) in the suckling piglets on d 14. These alterations may promote the hepatic cholesterol accumulation, which, in turn, activates hepatic bile acid metabolism and attenuates the relative expression levels of lipid metabolism-associated genes in the liver. However, the expression of CLOCK and BMAL1 and the lipid profile in the plasma and liver were not affected by COS supplementation on d 0. Collectively, our results indicate that maternal supplementation with COS postpartum up-regulates cholesterol accumulation in suckling piglets at age d 14, in part, by the regulation of circadian clock genes.     

Consumption of probiotic Lactobacillus rhamnosus (MTCC: 5897) containing fermented milk plays a key role in development of the immune system in newborn mice during the suckling–weaning transition

Early infancy, the period when offspring rely not only on their own immunity to combat food‐borne antigens but also acquire immunity through maternal sources (via transplacental routes and breast milk), is critical for immune system development Hence the present study was designed to evaluate the effect on offspring of administration of probiotic‐containing fermented milk (PFM) either to mothers during the suckling period or to their offspring after weaning either separately or sequentially. PFM‐fed mice showed enhanced leukocyte functionality in offspring as evidenced by significantly (P < 0.05) increased release of lysosomal enzymes (β‐galactosidase, β‐glucuronidase) in peritoneal fluid and nitric oxide production in culture supernatants of activated macrophages. Further, remarkably reduced levels (P < 0.01) of inflammatory markers (TNF‐α, monocyte chemotactic protein‐1) and allergic antibodies (total and milk specific IgE) were observed in offspring where PFM was fed either to them or to their mothers. However, considerably increased levels (P < 0.05) of SIgA were found in the guts of control and experimental groups animals irrespective of their exposure to PFM. Restoration of Th1/Th2 homeostasis further confirmed the useful effects of PFM supplementation by shifting the cytokine profile (IL‐4, IFN‐γ and IL‐10) with increased IFN‐γ/IL‐4 and reduced IgE/Ig2Ga ratios. Hence, it is logical to conclude that administration of Lactobacillus rhamnosus‐containing (MTCC:5897) fermented milk to mothers during the suckling period and to their offspring after weaning has beneficial effects on the development of newborns immune systems; this effect appears to be more pronounced when mothers are fed with it.     

The effects of short term calf removal on pulsatile LH secretion in the postpartum beef cow

Patterns of secretion of LH were characterized before, during and after 72 h calf separation at approximately 30 days postpartum in nine suckled cows. Calf removal increased both LH concentrations and LH pulse frequency (P<0.01) in the period 48 to 56 h following calf removal in six acyclic cows, but no changes were seen in three cyclic cows. Calf return decreased LH concentrations and LH pulse frequency (P<0.05) within 8 h in the acyclic cows, but no changes were seen in the cyclic cows. Differences in the initial LH parameters and magnitude of the LH responses were apparent between the acyclic cows which responded to calf removal with progesterone secretion and those which did not. These data suggest that suckling inhibits the release of LH acyclic cows and that this is achieved primarily via a reduction in the number of pulsatile releases of LH.     

Suckling behavior and its development in two Yangtze finless porpoise calves in captivity

We focally observed the suckling behavior of two Yangtze finless porpoise calves, C05 and C07, in captivity. Between 15 and 730 days postpartum of C05 and between birth and 30 days postpartum of C07, 286.3 (1.9 ± 0.4 hr/day (mean ± standard deviation), n = 148 days) and 18.3 hr (2.0 ± 0.5 hr/day, n = 9 days) of video footage were recorded, in which 429 and 111 suckling events were observed, respectively. We found that the calves made their initial suckling attempts after repeated stroking of the mother's body with their rostrums. The suckling duration was 4.4 ± 1.8 sec and 4.8 ± 2.4 sec, respectively. Before suckling, the calves swam under the mother's genital region (99.1% of number of event, respectively). During suckling, the mother generally turned sideways to facilitate the calves' suckling (80.7 and 76.6%, respectively). The calves almost equally used the two mammary slits [52.2% (left) and 47.8% (right), and 44.1% (left) and 55.9% (right), respectively]. The frequency and proportion of time C05 spent suckling continuously decreased to zero by 483 days postpartum. The two variables for C07 increased following birth, to a peak at 16 days postpartum, and then decreased continuously until 30 days postpartum. We discuss the possible implications of these observations for the management and conservation of this endangered cetacean.     

流行性出血热病毒对乳鼠致病特点的观察

本文观察了两株从病人体内新分离的流行性出血热(EHF)病毒114株和435株对乳鼠的致病特点,并在感染的乳鼠脑内找到了EHF病毒。免疫荧光检查发现,病毒抗原广泛存在于感染鼠的脑、肺、肝、肾等脏器。脑内和腹腔两条感染途径的比较发现,病毒抗原在上述脏器中的分布基本一致,但前者脑内的病毒感染滴度较后者高一个对数单位。对病毒的动态观察发现,EHF病毒首先在乳鼠腹腔感染6小时后的腹腔巨噬细胞(Mφ)中分离到、并持续阳性;病毒血症出现在感染后2天,随之在脑、肺、肝、肾和脾脏中查到。以上结果表明:EHF病毒对乳鼠具有广泛的嗜性,脑内感染途径能获得较高滴度的感染性病毒。提示EHF病毒在鼠mφ中增殖并携带至全身播散,可能是造成乳鼠全身性弥漫性感染的主要原因。     

In Vitro and in Vivo Evaluation of the Efficacy of Bovine Colostrum against Human Rotavirus Infection

We found that skimmed and concentrated bovine late colostrum (SCBLC) obtained from normal cows at 6–7 d after parturition exhibited high potency in inhibiting replication of human rotavirus (HRV) in vitro. Furthermore, prophylactic oral administration of SCBLC once before inoculation of HRV prevented the development of diarrhea in suckling mice in vivo. SCBLC from normal cows might be useful in the prevention of HRV-induced severe gastroenteritis in immunocompromised hosts.     

黄芪总黄酮对柯萨奇B3病毒感染乳鼠心肌细胞miRNA378和miRNA378*表达的影响

目的：研究柯萨奇B3病毒（CVB3）感染乳鼠心肌细胞miRNA378和miRNA378^*表达的作用。方法：原代培养乳鼠心肌细胞分3组（n=6）：对照组（正常细胞）、CVB感染组（正常细胞+CVB3）、黄芪总黄酮组（正常细胞+CVB3+黄芪总黄酮）。CVB感染组感染CVB3,黄芪总黄酮组感染CVB3同时给予黄芪总黄酮20 mg/L。采用免疫组化方法检测乳鼠心室肌细胞α-SMA蛋白,实时荧光定量PCR技术检测各组心肌细胞miRNA378及miRNA378^*表达。结果：①与对照组相比较,CVB感染组心肌细胞miRNA378及miRNA378^*表达明显减少（P<0.01）;②与CVB感染组比较,黄芪总黄酮心肌细胞miRNA378及miRNA378^*表达明显增加（P<0.01）。结论：黄芪总黄酮可以减少CVB3感染心肌细胞miRNA378及miRNA378^*表达。     

Maternal behavior,milk ejection,and plasma hormones in Hatano high- and low-avoidance rats

Hatano high- and low-avoidance (in a two-way active avoidance task) animals (HAA and LAA, respectively) were successfully selected from a Sprague-Dawley rat population. Pup growth of both strains was dependent on the maternal strain in a cross-fostering study. To determine whether there are strain-specific differences between HAA and LAA in maternal care, both strains of dams were subjected to a test battery as measured by nest building, home cage behavior, pup retrieval, and milk ejection tests. In addition, changes in plasma concentrations of lactotropic and corticotropic hormones such as prolactin, ACTH, and corticosterone were examined during lactation. The test battery indicated that the dams of both strains built good nests and spent an identical amount of time with their offspring. However, LAA dams showed a prolonged latency time for pup retrieval and often left pups outside the nest until the end of the test period. LAA dams also showed a decreased amount of milk ejection, whereas no strain differences were observed in milk ejection after oxytocin treatment. During lactation, a lesser increase in plasma concentrations of prolactin and a greater increase in ACTH were found in LAA dams. There were no differences between the two strains in plasma concentrations of corticosterone. These results clearly demonstrated decreases in maternal behavior and milk ejection in LAA as compared to HAA dams. The present results also suggest that maternal motivation and mechanisms responsible for maternal hormones related to suckling are involved in the degree of pup growth.     

Effect of linseed supplementation of the gestation and lactation diets of dairy ewes on the growth performance and the intramuscular fatty acid composition of their lambs

In this study, we investigated the effects of maternal gestation and/or lactation diets supplemented with extruded linseed (rich in 18:3n-3) on growth performance and long-chain polyunsaturated faaty acid (PUFA) accumulation in muscle tissues of suckling lambs. A total of 36 dairy ewes were fed a control diet (CON) and a diet containing linseed (LIN) during the last 8 weeks of gestation and/or the first 4 weeks of lactation. The four dietary treatments consisted of the following gestation/lactation feeding treatments: CON/CON, CON/LIN, LIN/LIN or LIN/CON. The lambs born from ewes fed the aforementioned diets were reared exclusively on milk and were slaughtered at 4 weeks of age. Profiles of ewes’ milk fatty acids and that of intramuscular fat (IMF) of leg muscles from lambs were determined. Compared with the CON/CON, LIN/CON offspring tended to grow slower and to have reduced cold carcass weights. Moreover, the LIN supplementation only in the prepartum period (LIN/CON) resulted in greater PUFAn-3 accumulation in the IMF compared with the CON/CON offspring due to increased 20:5n-3 (1.20 v. 0.64 mg/100 mg of total FA), 22:5n-3 (1.91 v. 1.46;) and 22:6n-3 (1.25 v. 0.89) contents, respectively. Compared with the CON/CON diet, providing LIN only during lactation (CON/LIN) caused a greater PUFAn-3 content in the IMF mainly due to a greater 18:3n-3 (1.79 v. 0.75 mg/100 g total FA) concentration. Continuous PUFAn-3 exposure, both via the maternal gestation and lactation diet, had no additive effects on PUFAn-3 accumulation in tissues. The results suggest that linseed, as an 18:3n-3 source, seems to be more efficient in increasing long-chain PUFAn-3 in fetal than in suckling lamb tissues.