Histochemical study of the interstitial tissue in scrotal and abdominal boar testes.

The present study describes the glycosidic content of the interstitial tissue in testes from healthy boars and from unilateral and bilateral abdominal cryptorchid boars using lectin histochemistry. The Leydig cells of healthy boars contained glycans with fucosyl, mannosyl, glucosyl, neuraminic acid and galactosyl residues, which have structural and transport functions, and participate in androgen synthesis and in cell regulation. Unilateral cryptorchidism induced high glucosyl and low galactosyl content in the Leydig cells of scrotal testes, resulting in impaired androgen production. In abdominal testes, the Leydig cells exhibited increased amounts of glucosyl and reduced amounts of galactosyl and neuraminic acid residues, resulting in defective cell regulation and lack of androgen synthesis. In healthy boars, the extracellular glycans contained fucosyl, galactosyl, glucosyl and neuraminic acid residues, which confer viscoelasticity on the interstitial tissue and participate in substrate transport, hormone binding and cell-cell interaction. Unilateral cryptorchidism did not induce anomalies in extracellular glycans in scrotal testes, but unilateral and bilateral cryptorchidism resulted in an increased content of fucosyl and galactosyl, and a decreased content of glucosyl and neuraminic acid residues in abdominal testes, leading to reduced viscoelasticity and defective substrate transport across the extracellular matrix.     

Effect of local scrotal heating on the expression of tight junction‐associated molecule Occludin in boar testes

The aim of this study was to determine whether local scrotal heating (42°C, for 1 hr) had an effect on the expression of tight junction (TJ)‐associated molecule Occludin in boar testes. Adult boars (Landrace, n = 6) were used and randomly divided into two groups (n = 3 each). Three boars were given local scrotal exposure to 42°C for approximately 1 h with a home‐made electric blanket of controlled temperature as local scrotal heating group, the other three boars received no heat treatment and were left at standard room temperature as control group. After 6 hr, all boars were castrated and the testes were harvested. qRT‐PCR, Western blotting and immunohistochemistry were used to explore the expression and localization of Occludin. qRT‐PCR and Western blotting showed that the protein and mRNA levels of Occludin significantly decreased in local scrotal heating group as compared to the control. Furthermore, immunoreactivity staining of Occludin was localized at the sites of the blood–testis barrier (BTB) and formed an almost consecutive and strong immunoreactivity strand in the control, while Occludin was limited to Sertoli cells (SCs) and no obvious immunoreactivity strand was present in local scrotal heating group. These data indicated that local scrotal heating decreased the expression of TJ‐associated molecule Occludin, which may be involved in heat‐induced spermatogenesis damage.     

环境温度、湿度等因素对家禽体温调节的影响及评估模型

温热环境是影响家禽福利、健康以及生产性能的重要因素。家禽属恒温动物,当环境温度、湿度等因素改变时,可通过调节自身产热和散热维持体温恒定,因此家禽体温调节的变化是反映温热环境舒适程度的重要指标。本文针对环境温度、湿度、风速对家禽产热量、采食量、蒸发散热量、呼吸频率、皮肤温度、深层体温等体温调节指标的影响进行了总结和分析,为今后研究、建立家禽舒适环境模型,科学调控家禽舍内温热环境提供参考。     

Effects of ambient temperature and scrotal fleece cover on scrotal and testicular temperatures in rams.

The objective was to determine scrotal and testicular temperatures in rams and how they are affected by ambient temperature (10 degrees C vs 25 degrees C) and scrotal fleece (densely fleeced vs shaved). Scrotal surface temperatures (SST) of the caudal aspect of the shaved hemi-scrotum at 10 degrees C vs 25 degrees C were (mean, degrees C) 28.9 and 30.5 (P < 0.03), 28.2 and 29.6 (P < 0.04), and 26.1 and 27.6 (P < 0.06) at the top, middle and bottom of the testis, respectively. Scrotal subcutaneous temperatures (SQT) on the fleeced vs shaved side were 33.5 and 32.0 (P < 0.02), 32.2 and 31.1 (P < 0.06), and 31.7 and 30.8 (P < 0.09) at the top, middle, and bottom at 10 degrees C; they were 33.9 and 32.1 (P < 0.02), 33.1 and 31.9 (P < 0.05), and 32.5 and 32.0 (P < 0.15) at 25 degrees C. Intratesticular temperatures (ITT; measured only at 25 degrees C) on the fleeced vs shaved side were 35.3 and 35.0 (P < 0.5), 35.5 and 35.2 (P < 0.4), and 35.4 and 35.0 (P < 0.3) at the top, middle, and bottom. Temperature gradients (difference from top to bottom) were greatest for SST (2.8 degrees C), moderate for SQT (1.8 to 0.1 degrees C), and not significant for ITT (-0.1 and 0.1 degrees C). The SST was approximately 1.5 degrees C warmer at all 3 locations at 25 degrees C vs 10 degrees C. Increased ambient temperature affected SQT more at the bottom than at the top. Conversely, the difference in SQT between the fleeced and shaved sides was greatest at the top. The difference in ITT (0.3 degrees C warmer on the fleeced vs the shaved side at all locations) was not significant. Therefore, the magnitude of temperature increase associated with ambient temperature or scrotal fleece was affected by both depth and vertical location.     

Clinical coccidiosis in a boar stud.

This report describes an outbreak of coccidiosis in a boar stud. A live, untreated, adult boar with a history of diarrhea was submitted to the Iowa State University Veterinary Diagnostic Laboratory, Ames, IA. For a 3-month period, approximately 40% of the boars in this stud had developed gray to brown diarrhea that lasted 1-3 days. Affected boars did not lose condition, and antibiotic therapy did not appear to affect the clinical course ofthe disease. At necropsy, the distal ileum was palpably thickened and covered by a thick, yellow-green, fibrinous exudate. Microscopic changes in the ileum consisted of an erosive enteritis associated with the presence of numerous coccidia within mid to superficial villus enterocytes. The mucosa was covered by a fibrinous exudate admixed with numerous nonsporulated coccidian oocysts. A light growth of Salmonella enterica serovar Derby was isolated from the small intestine of this animal, but laboratory tests were negative for Lawsonia and Brachyspira spp. Individual or paired fecal samples were obtained from 6 additional boars experiencing similar clinical signs. Numerous Eimeria spinosa oocysts were identified in these samples. Neither Salmonella nor Brachyspira spp. were cultured from submitted fecal samples. Necropsy of a live boar and examination of feces from 6 additional animals confirmed that the mild, sporadic, transient diarrhea in this boar stud was due to coccidiosis.     

Evidence for Thermoregulation in the Tortoise Chersine Angulata

The results of experiments on Chersine angulata suggest that a mechanism exists for controlling rate of change of body temperature over the range 20-35°C. Active retardation of heat uptake close to the upper temperature is a prominent feature as measured by cloacal temperature. Unlike other reptiles so far studied, Chersine angulata, when alive, cools more rapidly than it heats up. Dead animals heat and cool at the same rate, and more rapidly than live animals. It is suggested that overheating is the critical factor in the thermal relations of the tortoise.     

Thermoregulation and performance of British Anglo-Nubian and Saanen goats reared in an intensive system in Trinidad

Anglo-Nubian and Saanen goats were imported into Trinidad and Tobago to form the nucleus of the goat expansion and improvement programme. Thermoregulation and performance of the parent stock and the F1 were evaluated under intensive housing and management. Rectal temperature in the a.m. irrespective of breed or season ranged from 38.5°C to 38.7°C and p.m. ranged from 38.8°C to 39.0°C. After 2 h of exposure outdoors without shade, Saanen parent stock (SAPS) respiration rate (105 br/min) was significantly higher (p < 0.001) than Saanen F1 (SAF1, 76 br/min), Anglo-Nubian parent stock (ANSP, 65 br/min) and Anglo-Nubian F1 (ANF1, 51 br/min). Rectal temperature over the same period showed significant differences (p < 0.042) between SAF1 (39.8°C) and SAPS (39.4°C), and ANF1 (39.4°C); the value for ANSP was 39.7°C. Age at first kidding showed no significant difference (p > 0.05) between breeds or between the parent stock and the F1 generations, ranging from 638 to 686 days. The ANPS were the most prolific of all groups (p < 0.05); the mean for this group was 1.86 ± 0.07 kids/kidding. Saanen F1 was the least prolific among the group, with mean number of kids at 1.23 (±0.11) kids/kidding. Kidding interval showed no significant (p > 0.05) difference between the groups, ranging from 319 to 521 days. It was concluded that the Anglo-Nubian appears to be more suitable than the Saanen for the tropical humid environment in Trinidad as indicated by their thermoregulation, prolificacy and kidding interval.     

Plasma concentration profiles of gonadotrophins and testosterone in the adult boar.

Follicle stimulating hormone, luteinizing hormone and testosterone were measured by radioimmunoassay in plasma samples collected at 15 min intervals for a 12 h period in eight adult boars. Pulse increases in follicle stimulating hormone concentrations varied from one to four between individual boars while those of luteinizing hormone ranged from zero to four. The index of hormone production, provided by calculation of the area under the curve, was 0.5 +/- 0.51 microgram/L (means +/- S.D.) for follicle stimulating hormone and 0.46 +/- 0.11 microgram/L (means +/- S.D.) for luteinizing hormone. A significant correlation between changes in follicle stimulating hormone and luteinizing hormone values was seen in only two boars. The mean plasma testosterone concentration was 7.43 +/- 1.58 nM/L (means +/- S.D.). An identified increase in testosterone values occurred once in the 12 h period for six of the boars but was not noted in the other two animals. Although increases in testosterone could be identified with a previous pulse of luteinizing hormone, not all luteinizing hormone pulses were followed by an elevation in testosterone. A significant correlation between luteinizing hormone and testosterone was present in three of the eight animals. Follicle stimulating hormone and luteinizing hormone were measured in samples similarly collected two weeks after castration in the same eight boars. The number of pulses of follicle stimulating hormone increased significantly (p less than 0.05) and ranged from 3 to 7/12 h. The index of production of 1.8 +/- 1.15 micrograms/L (mean +/- S.D.) also represented a significant increase (p less than 0.05) over precastration follicle stimulating hormone values.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of housing system and boar exposure on estrus expression in weaned sows

Reproductive efficiency depends on detection of estrus, which may be influenced by housing and boar exposure. This experiment investigated the effects of housing system and boar contact on measures of estrus in weaned sows. Mixed-parity sows were randomly assigned to be weaned into gestation crates away from boars (AWC, n = 45), into pens away from boars (AWP, n = 42), or into pens adjacent to a mature boar (ADJ, n = 46). Estrus detection was initiated at approximately 0700 (0 h) and again at 0.25-, 0.5-, 1-, 2-, 4-, and 8-h intervals beginning on d 4 and continuing through d 7 following weaning. Estrus detection involved observation of the standing response after application of nose-to-nose boar exposure, backpressure, and side rubbing. For the AWC sows, a mature boar was moved to the front of the crates for a 10-min period and then removed. Sows housed in AWP were moved approximately 15 m to an empty pen adjacent to a mature boar for a 10-min period, and then returned to their pen. Sows housed ADJ were not moved and estrus detection was performed in their home pen for a 10-min period. The proportion of sows expressing estrus within 7 d from weaning was lowest for ADJ (80%, 37/46) compared with AWP (98%, 41/42) and AWC (96%, 43/45; P < 0.05). There was an effect of interval from weaning to estrus on the percentage of sows expressing estrus, but there was no interaction with treatment. Sows in AWC and AWP (4.7 d) had decreased (P = 0.01) intervals from weaning to estrus compared with ADJ (5.2 d). The duration of estrus was also shorter (P < 0.001) for ADJ (45 h) compared with AWC (58 h) or AWP (62 h). There was a treatment x interval x day of estrus effect for the percentage of sows expressing estrus. After detection of the first standing response on the first day of estrus, only 62 to 82% of sows were detected standing over the next 2 h for all treatments. However, at 4 to 8 h, this increased to 85 to 98% for the AWC and AWP sows, but <73% of the ADJ sows were detected during this period. On the second day of estrus, estrus expression was not influenced by interval for the AWC and AWP sows and was between 90 to 100% during the 8-h period, whereas ADJ sow detection rates were between 68 to 88%. These data suggest that housing sows adjacent to boars negatively affects estrus expression and detection. In addition, refractory behavior occurs in approximately 30 to 40% of sows and is influenced by housing relative to the boar, day of estrus, and interval from last boar exposure.     

The acrosin system of bull, boar and ram sperm]

Described in this paper is a technique by which to separate the components of the sperma acrosin system. Included in the method are extraction of all components by means of acetic acid, separation of acrosin inhibitors on Sephadex G 100 as well as biochemical determination of proacrosin and acrosin. While species-related peculiarities were of minor importance, alterations were found to occur to the acrosin system in response to deep-freeze preservation of bull, boar, and ram sperma. Those alterations grew manifest primarily through decline in total acrosin activity and shifting of the proacrosin-acrosin ratio in the direction of proacrosin activation. Detachability of membrane-bound acrosin inhibitors was increased with significance, following in-vitro capacitation of bull sperma under heparin action.     

Scanning electron and light microscopic studies of the surface epithelium of the rete testis and epididymis of the boar. I. Rete testis and efferent ducts

The use of the scanning electron microscope gave a three dimensional representation of the epithelial surface. Additionally, light microscopy revealed the representative structure of the epithelium. The rete testis showed a single layer of cubic epithelial cells. Short and dense microvilli were found on the surface. Sporadically a single, cilia-like structure was recognized. An extratesticular rete testis was identified. The flowing transition of the epithelium between the rete testis and the efferent ductuli occurred at different levels, so that both kinds of epithelial structures were recognized in the same area. The efferent ductuli were composed of a single columnar epithelium consisting of two cell types, principal cells and ciliated cells. The ciliated cells were recognized by their cilia protruding into the lumen. The principal cells showed microvilli on their surface and bleblike apical protrusions which erupt into the lumen.     

Effects of GnRH treatment on scrotal surface temperatures in bulls.

Two experiments were conducted to characterize scrotal surface temperature (SST) in bulls treated with gonadotropin releasing hormone (GnRH). In Experiment 1, Angus bulls (n = 10, 18 mo, 597 kg) were given GnRH (400 ng/kg) or saline, IV. Bottom SST increased approximately 1.7 degrees C (P < 0.005) over time (0 to 90 min) at an ambient temperature of 5 degrees C. However, there was no significant effect of GnRH treatment and temperature increases were attributed to stress. When the experiment was repeated at an ambient temperature of 25 degrees C, SST was elevated prior to treatment, with no subsequent significant increase. Experiment 2 was conducted with Charolais bulls (n = 6, 12-14 mo, 517 kg) with an emphasis on minimizing stress. Bottom SST increased approximately 2 degrees C (P < 0.05) between 0 and 45 min after GnRH treatment, supporting the hypothesis that GnRH treatment increases SST in bulls. In conclusion, it was apparent that stress, high ambient temperatures, and GnRH treatment can all increase SST in bulls.