摘要: |
为了解小黄鱼(Larimichthys polyactis)消化道结构特点及其功能与食性的相关性,采用解剖、石蜡切片、AB-PAS反应及酶活检测技术,观察研究了小黄鱼消化道的形态及组织学结构、黏液细胞定位及消化酶活性。结果显示:消化道由口咽腔(舌)、食道、胃及肠构成,食道粗短,胃卜型,肠呈"S"型弯曲,肠指数为0.63;舌上皮中分布有味蕾及少量各型黏液细胞。食道、胃及肠均由黏膜层、黏膜下层、肌层及外膜组成;食道含初级及次级突起,分别被覆复层扁平及单层柱状上皮,大量黏液细胞分布于复层上皮内,以Ⅱ型为主。胃内胃腺发达,分布有大量Ⅰ及Ⅱ型黏液细胞;胃中蛋白酶活性较高。肠上皮为单层柱状上皮,上皮层分布有各型黏液细胞,以Ⅱ型为主;肠道肌层厚度、黏膜褶皱高度及黏液细胞总密度由前往后递增;肠道中胰蛋白酶、脂肪酶、淀粉酶及碱性磷酸酶活性较高,且后肠高于前、中肠。小黄鱼消化道形态、组织结构及酶活性分布特点与其肉食食性相适应,口咽腔(舌)及食道上皮具有较好的保护作用,胃在蛋白质消化吸收方面发挥重要作用,肠道在蛋白质、脂类、糖类、无机盐等物质的消化吸收方面起重要作用。 |
关键词: 小黄鱼(Larimichthys polyactis) 解剖学 组织学 黏液细胞 消化酶 食性 |
DOI:10.11693/hyhz20190200043 |
分类号: |
基金项目:浙江省科技计划项目,2017C02013号;国家自然科学基金项目,U1809212号。 |
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MORPHOLOGY, HISTOLOGY AND DIGESTIVE ENZYMES OF THE DIGESTIVE TRACT OF THE SMALL YELLOW CROAKER LARIMICHTHYS POLYACTIS |
CHEN Yin-Er1, ZHENG Xue-Bin1, GAO Xin-Ming1, WANG Jing-Qian1, XIE Qing-Ping2,3, ZHAN Wei2,3, LOU Bao2,3, ZHU Jun-Quan1
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1.Key Laboratory of Applied Marine Biotechnology, Ministry of Education, Ningbo University, Ningbo 315211, China;2.Marine Fisheries Research Institute of Zhejiang, Zhoushan 316100, China;3.Zhejiang Academy of Agricultural Sciences, Hangzhou 310016, China
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Abstract: |
To study the relationship between feeding habits and structural characteristics and functions of the digestive tract of the small yellow croaker Larimichthys polyactis, we used anatomical, histological, histochemical (AB-PAS), and enzymological techniques to observe the morphological and histological structure, mucous cell distribution, and digestive enzyme activity. These observations show that the digestive tract consists of four parts:an oropharyngeal cavity, a short but thick esophagus, λ-shaped stomach, and S-shaped intestine with index of 0.63. In the oropharyngeal cavity, four types of mucous cell were observed in the epithelium of tongue. The three other parts-the esophagus, stomach, and intestine-consist of mucosa, sub mucosa, muscle layer, and serosa tissues. The esophagus shows a stratified squamous epithelium on the primary fold, a single columnar epithelium on the secondary fold, and a large number of mucous cells localized to the stratified epithelium, which are dominated by Type Ⅱ mucous cells. The stomach is abundant in gastric glands and Types I and Ⅱ mucous cells; a high level of pepsin activity was also detected. In the intestine, four types of mucous cells, dominated by Type Ⅱ cells, were observed on the surface of the single columnar epithelium. The thickness of the muscle layer, mucosal fold height, and total density of mucous cells increase from the anterior to the posterior intestine. In addition, relatively stronger trypisn, amylase, lipase, and alkaline phosphatase activities were detected in the intestine. Compared to the anterior or mid-intestine, the posterior intestine shows a higher level of activity. This study reveals that the morphological and histological characteristics and digestive enzyme activity in the digestive tract of L. polyactis have been well developed and adapted to its carnivorous feeding habits. The epithelium of the oropharyngeal cavity and esophagus inhibit bacterial infection and prevent damage. The stomach plays an important role in digesting and absorbing proteins, and the intestine is crucial in absorbing proteins, lipids, carbohydrates, and inorganic salts. |
Key words: Larimichthys polyactis anatomy histology mucous cell digestive enzyme feeding habit |