父母代固始鸡空肠的发育形态学研究

应用大体解剖学与组织学切片技术,对父母代固始鸡空肠的发育形态学进行了研究,并用Logistic曲线方程对空肠重量增长进行拟合。结果表明:空肠的长度、重量、周长和空肠的绒毛长度、绒毛宽度、隐窝深度、肠腺宽度与周龄呈正相关;空肠指数、空肠的肠腺密度与周龄呈负相关;Logistic方程可以很好地拟合空肠的增重曲线(公鸡R2=0.9968,母鸡R2= 0.9891),公鸡的空肠增重拐点是8.26周,母鸡是8.64周。     

父母代固始鸡空肠的发育形态学研究

应用大体解剖学与组织学切片技术,对父母代固始鸡空肠的发育形态学进行了研究,并用Logistic曲线方程对空肠重量增长进行拟合.结果表明:空肠的长度、重量、周长和空肠的绒毛长度、绒毛宽度、隐窝深度、肠腺宽度与周龄呈正相关;空肠指数、空肠的肠腺密度与周龄呈负相关;Logistic方程可以很好地拟合空肠的增重曲线(公鸡R2=0.9968,母鸡R2=0.9891),公鸡的空肠增重拐点是8.26周,母鸡是8.64周.     

商品代固始鸡在放牧饲养条件下生长发育规律的研究

根据商品代固始鸡在放牧饲养条件下体重及体型参数的实测数据,分析了其在4～18周龄阶段的生长育情况,并给出体重、胫长、体斜长、胸骨长对日龄的拟合回归曲线方程。     

父母代固始鸡十二指肠的发育形态学观察

应用大体解剖学和组织切片技术,对0～20周龄父母代固始鸡的十二指肠进行了发育形态学研究.结果表明,十二指肠的长度、体质量、周长和肠绒毛的长度、肠腺隐窝的深度、肠腺宽度及各肌层厚度等指标随周龄的增加而增长;十二指肠相对生长率、肠腺密度和十二指肠指数则呈下降趋势;肠绒毛有分支现象;淋巴组织的发育比较缓慢,到6周龄后才出现有淋巴小结;通过建立Logistic方程模型模拟十二指肠重量的生长变化,得到其生长方程:♂:Y=9.72/(1 15.3le-0.33t),♀:Y=8.29/(1 12.50e-0.31t).     

不同性别固始鸡生长曲线的分析

用Logistic曲线方程,对固始鸡0～12周龄体重曲线进行拟合。结果表明,Logistic曲线方程可以很好地拟合固始鸡的生长曲线(公鸡:R2=0.9877,母鸡:R2=0.9950)。6.9周是固始公鸡的生长转折点,6.4周是固始母鸡的生长转折点。     

固始鸡免疫器官指数的发育规律研究

为研究固始鸡免疫器官指数的发育规律,应用大体解剖学方法,经过SAS(6.12)软件对数据分析处理,结果表明,雄性和雌性固始鸡活体重、免疫器官重量和指数之间存在差异(P<0.01),但免疫器官生长发育规律相似;1周龄～20周龄内,前期固始鸡活体重和免疫器官重量均呈上升趋势,后期活体重仍增加,而免疫器官重量维持较平稳水平.随着固始鸡的生长发育,不同免疫器官指数总体而言均呈下降趋势,免疫器官生长速度小于增重速度.     

南京地区藏獒的生长发育性状研究

对南京地区引入藏獒的初生、50日龄断奶、3月龄、6月龄、12月龄、18月龄、24月龄(成年)的体重和体尺性状进行了测定和分析.结果表明,南京地区引入藏獒在3～6月龄时,其生长发育强度达到最大值;各项体征指标的累积生长符合动物的一般生长曲线;与河曲藏獒相比,24月龄的南京引入藏獒其体重较轻,分别为同一生长期河曲藏獒的66.9%(公犬)和53.7%(母犬),其余体尺指标两地藏獒的差距不大.     

内蒙古罕山白绒山羊毛囊生长规律的研究

用sacpic染色法对周岁内蒙古罕山白绒山羊体侧部皮肤横切、纵切面进行染色,研究其毛囊生长发育的规律.结果表明,一年当中,5月份次级毛囊逐渐开始发育;6、7、8月份次级毛囊发育显著(P＜0.05);9、10、11、12月份次级毛囊发育极显著(P＜0.01),其中11月份的发育最好;1、2月份进入退行期;3、4月份进入休止期.次级毛囊深度在8月底最深,毛球宽、毛囊宽也在8月底最宽.退行期的毛囊活性低,休止期的毛囊完全失去活性,表现为绒毛停止生长.绒长度测量结果表明,5月份少数个体的绒长出体表皮;6、7、8月份绒长度逐渐增长,但差异不显著(P＞0.05),9、10、11、12月份绒长度显著增加,其中11月份最长(P＜0.01).     

Breeder age affects small intestine development of broiler chicks with immediate or delayed access to feed

1. The relationship between breeder age and chick gastrointestinal tract development to 21 days of age, as influenced by immediate or delayed access to feed, was examined in three consecutive trials.

2. Ross 708 chicks, derived from breeder flocks at 31 (young), 40 (middle) and 63 (old) weeks of age were placed randomly into either a control group with immediate access to feed and water, or a 48?h feed delayed (FD) group with free access to water.

3. FD negatively affected body weight (BW) of chicks derived from young and old flocks through the first and second weeks of age, respectively. Chicks from the older flock absorbed more yolk in the first 48?h with no FD effect. When feed was made available, chicks from the FD group showed a large increase in small intestine weight relative to BW, surpassing (P? 4. Morphological measurements in all intestinal sections had higher values in chicks derived from the middle age breeder flock. FD to newly hatched chicks from the young breeder flock shortened villi (P?P? 5. Crypt depths were maximised between 7 and 14?d post-hatch in chicks from young and old breeder flocks, but crypt depths in chicks from the middle aged flocks continued to deepen.

6. The increased crypt depth may augment the number of enterocytes available for villus growth, and facilitate longer villi and greater villus surface area, in chicks from the middle age flocks. Intestinal morphological variation was associated with breeder flock age, which accounted for differential growth in chicks derived from young, middle, and old aged breeder flocks.     

Development of the small intestine in heavy and light strain chicks before and after hatching

1. Intestinal development was examined in Arbor Acres and Lohmann chicks from one week before hatching until one week after. Changes in morphology and concentrations of DNA, RNA and protein in the duodenal tissue were determined.

2. Villus height and perimeter increased 9 to 11 fold from day 14 of incubation until 7 d after hatching. Arbor Acres chicks had values which were consistently higher than Lohmann chicks.

3. DNA concentration of duodenal tissue increased with age in parallel to the increase in the number of enterocytes per villus. In the pre‐hatch period tissue activity as indicated by RNA/DNA, and ribosomal capacity as shown by the RNA/protein ratios, were high for both strains; values for Arbor Acres embryos and chicks were greater than for Lohmann.

4. DNA concentrations, RNA/DNA, RNA/protein and protein/DNA ratios correlate with morphological measurements and can be used as additional criteria for evaluating development in chick intestine.

5. In the last week of incubation and immediately after hatching, intestinal growth appears to arise mainly from cellular hyperplasia and not from cellular hypertrophy. Intestinal development patterns were similar for both strains but growth was more rapid in Arbor Acres chicks.     

Effects of breeder age and egg weight on morphological changes in the small intestine of chicks during the hatch window

1. The objective of the study was to investigate the effects of breeder age and egg weight on hatching performance and morphological changes in segments of the small intestine of broiler chicks during a 21 h hatch window.

2. Eggs from Ross broiler breeder flocks aged 29 (young) and 48 weeks (old) were classified as light (LE) or heavy (HE) and incubated at the same conditions. At 475 h of incubation, eggs were checked every 3 h to determine time of external pipping and hatching. The first 42 chicks to emerge from each group were weighed and chick length was measured and 14 chicks from each group were sampled to collect residual yolk and intestine segments. The rest of chicks were placed back in the incubator and chick weight and length were measured individually at 9, 15 and 21 h after chicks hatched. At the end of 21 h, 14 chicks from each group were sampled again and the same procedure was followed.

3. The HE chicks pipped and hatched later than LE, regardless of breeder age. From hatch to the end of the hatch window, chick weight, but not yolk-free chick weight, gradually reduced. Relative residual yolk weight of chicks from both egg weights was similar at hatch, however, yolk sac utilisation was higher for LE chicks during the 21 h post-hatch period. At hatch, jejunum and ileum villus development was very similar for HE and LE chicks but greater development was observed for villus area with an increase in the jejunum villus length, width and goblet cell numbers in HE chicks.

4. The longest jejunum villus and the widest duodenum and jejunum villus were obtained for HE chicks from old breeders indicating that HE chicks from old breeders would have a greater surface area for nutrient absorption.     

Dimensions and histologic characteristics of the small intestine of dogs during postnatal development

OBJECTIVE: To quantify dimensions of the small intestine of dogs and describe changes in histologic characteristics of the mucosa during postnatal development. SAMPLE POPULATION: Gastrointestinal tract tissues obtained from 110 Beagles (15 adult females and 95 puppies of both sexes). PROCEDURE: Several variables (length, total weight, mucosal weight, and nominal surface area) of the small intestine were measured in puppies at birth but before suckling; 1 day after birth and subsequent suckling, 21, 42, and 63 days after birth, and in the adult dams of the puppies. Tissue structure was examined and quantified at each time point by use of routine histologic examination and ocular micrometry of formalin-fixed specimens stained with H&E. RESULTS: Small intestinal dimensions increased throughout development with the greatest proportional changes during the first day after birth and onset of suckling. Villus height decreased during suckling but had consistent values from 42 days after birth to maturity, whereas crypt depth increased from birth to maturity. Vacuolated enterocytes were evident from birth to 21 days but not thereafter. CONCLUSIONS AND CLINICAL RELEVANCE: Increases in intestinal dimensions provide growing dogs with a greater capacity for digestion and absorption. Changes in mucosal architecture and cell populations coincided with shifts in dietary inputs. These findings may assist in the diagnosis of small intestinal diseases and nutritional responses during growth and development of dogs.     

Differences in the development of the small intestine between gnotobiotic and conventionally bred piglets

The effects of age, weaning and breeding conditions on the small intestinal morphology and the distribution of immunocompetent cells were investigated. The villus height and numbers of CD3+ T-lymphocytes, measured in the duodenum, jejunum and ileum, were determined in both the gnotobiotic and conventionally bred piglets. The diet of gnotobiotic piglets was composed of milk-replacement and feed mixtures. The application of milk replacement was finished on day 28. Conventional piglets were fed on sow's milk and feed mixtures. The animals were weaned on day 28. Small intestines were collected from 12 conventional and 12 gnotobiotic piglets slaughtered at the age of 2, 7, 14, 21, 28 and 35 days. The morphology results demonstrated that duodenal and ileal villi were significantly higher (p < 0.001) in gnotobiotic piglets during the entire period of the experiment. However, the weight of conventional piglets was higher during the experiment, in some cases significantly (p < 0.05). A marked reduction, in some cases significant (p < 0.001, p < 0.01 respectively), of the villi height on day 7 after the diet change for both groups of animals was recorded. The results demonstrate the differences in the gut development between both groups and their relationship to the breeding conditions. Nevertheless, the effect of crucial diet changes was observed independently of them. The immunohistochemistry results showed significantly (p < 0.001, p < 0.01 respectively) higher numbers of CD3+ T-lymphocytes in the jejunal villi of conventionally bred piglets. Similar results, in some cases significant (p < 0.001, p < 0.01 respectively), were also obtained from the other parts of the small intestine. These observations confirm reduced microorganism exposure under the gnotobiotic conditions.     

The occurrence of Clostridium perfringens in the intestine of chicks

Commercial broiler chicks brooded either on wire or on used or new litter demonstrated a 75% (62/75) incidence of recovery of "perfringens-like" colonies from the intestine during a 5-week period. Eleven Clostridium spp. were identified from among these "perfringens-like" organisms, which were cultured on SPS selective agar medium. Clostridium perfringens was positively identified only infrequently (five isolates) from among the "perfringens-like" colonies. In contrast, "perfringens-like" colonies were not recovered from the intestinal contents of specific-pathogen-free chicks reared in an isolation unit. However, C. perfringens was isolated from the yolk sac of one embryonated egg and from the intestine of a single 7-day-old chick, indicating the possibility of vertical transmission of this potential pathogen.