Indian Journal of Veterinary Anatomy 32 (1): 26-28, June 2020 Morphology of the Liver of Asian Elephant (Eelephas maximus indicus) C.V. Rajani1*, H.S. Patki2, K.P. Surjith3, S. Patgiri4, P.M. Deepa5 and D. Abraham6 Department of Veterinary Anatomy and Histology College of Veterinary and Animal Sciences, Pookode Wayanad-673 576 (Kerala) Received: 05 June 2020; Accepted: 06 June 2020 ABSTRACT The study was conducted on liver collected from an elephant calf and 5 adult domesticated Asian elephants. After recording gross morphological features, liver samples were processed for routine histological procedures. Liver had four borders viz., dorsal, ventral, left lateral and right lateral. Caudal vena cava crossed the dorsal border and the ventral border had a deep umbilical fissure. Parietal surface presented straight line of attachment of Falciform ligament and an inverted arc-like coronary ligament. Visceral surface had a wide hepatic porta and attachment of lesser omentum. Liver had two chief lobes: a larger right lobe and an undivided left lobe. The round ligament was attached to the right medial lobe. Liver did not adhere to right kidney. Gall bladder was absent. Liver showed dense Glisson’s capsule. The hepatic lobules were indistinctly delineated and irregularly hexagonal. Radiating, branching laminae of hepatocytes and intervening anastomosing sinusoids constituted the parenchyma. Small squamous endothelial cells and large Kupffer cells lined the sinusoids. Portal triads were observed at the periphery of the lobule. The present study established the morphological and histological characteristics of liver in Asian elephant. Key words: Asian elephant, Morphology, Histology, Liver, Hepatocytes Anatomical features on viscera of wild animals are diaphragm. It had firm texture and had a reddish brown limited. Morphology of liver had been reported in foetal colour. Surface of liver presented distinct lobation. The elephant (Mariappa, 1985). Thitaram et al. (2018) liver from a female elephant calf of about two months old described in brief on microscopic structure of liver in had a weight of 1.5 Kg and the weight in adult elephants juvenile elephant. Salient information on morphology and was 30-35 Kg. Liver had two surfaces namely cranial histology of liver in Asian elephant is scarce. Hence, the (parietal) and caudal (visceral) surfaces (Figs. 1, 2). In present study was envisaged to ascertain the unique gross situ, the parietal surface of liver was strongly convex in and histological features of liver of elephant. both transverse and dorso-ventral direction as described by Mariappa (1985) in elephant calf. Its visceral surface MATERIALS AND METHODS was concave especially at the hepatic porta where it was The study was conducted on liver of an elephant deeply concave. However, when the organ was removed calf and 5 adult domesticated Asian elephants died due to from the body, it flattened and lost its exact shape. The natural causes in Central Kerala. The specimens were liver as a whole had four borders viz., dorsal, ventral, left collected during post-mortem examination. Permission for lateral and right lateral. The dorsal border was concave, the conduct of the study was obtained from Chief Wildlife and the caudal vena cava crossed obliquely along its mid- Warden, Kerala as per order no KFDHQ-915/2019- length. The vessel later extended along the dorsal part of CWW/WL10 dated 11/03/2019. During necropsy, the liver parietal surface. The medial part of dorsal border presented was carefully separated and gross morphological oesophageal notch. Left lateral border was convex, thin parameters were recorded. The tissue samples were at dorsal part; however it was much thicker and bulky at preserved in 10% Neutral Buffered Formalin; and the ventral most end. Right lateral border was thick and processed for routine paraffin embedding procedures. 5 convex. The thick ventral border presented deep umbilical µm thick sections were cut and stained by Haematoxylin fissure and a wide notch at its junction with the right lateral and Eosin (Singh and Sulochana, 1996). border. RESULTS AND DISCUSSION The parietal surface of the right central lobe at its centre had the falciform ligament which attaches liver to The liver was placed in the medial plane within the the diaphragm (Fig. 1). It was nearly straight and extended intra thoracic part of abdominal cavity, just caudal to almost up to the dorsal border where it diverged to form 1,2,3Asstt. Prof.; 4 M.V.Sc. Student; 5 Asstt. Prof., VPHE; 6 Asstt. inverted arc-like coronary ligament. The right and left limbs Forest Vety. officer, Thrissur *Corresponding author: [email protected] of coronary ligament encircled caudal vena cava. An 26 Rajani et al. elongated area nuda was observed along the right dorsal between left lobe and quadrate lobes. Moreover, umbilical border. Coronary ligament continued as right and left fissure and round ligament defined a small quadrilateral triangular ligaments. The position and arrangement of area which resembled quadrate lobe of domestic animals coronary ligaments and caudal vena cava in elephant was (Nickel et al., 1979). Further, liver did not present a distinct similar to descriptions in pig (Nickel et al., 1979). The caudate lobe or any notch or impression of the right kidney. ventral free end of falciform ligament continued caudally Hepatic porta in the form of a deep extensive fissure as round ligament, which was quite distinct as a thick chord was present on the middle of visceral surface and extended in the elephant calf. On the visceral surface, attachment mainly on right lobe. The porta enclosed large, thin portal of lesser omentum extended from the oesophageal notch vein; thick hepatic artery and a bile duct. A chain of 8-10 and encircled the hepatic porta. lymph nodes of various sizes circumscribed the hepatic The deep umbilical fissure that divided the liver into porta (Fig. 3). The nodes varied in size from few mm to 2- two chief lobes: a larger right lobe and an undivided left 3 cm. The lymph nodes were round to oval, elongated or lobe (Figs. 1,2). The undivided left lobe resembled a hemi- strip-like in outline. Right and left lobes of liver had their circle. The right lobe as a whole was bean shaped. Further, own hepatic ducts which combine to form the main hepatic a wide notch of right lobe indicated its division into right duct. Gall bladder was absent as recorded by Mariappa (1985) in elephant foetus and Sreeranjini et al. (2011) in medial and right lateral lobes. Lobations of liver in general sambar deer. However, gall bladder is recorded in wild agree with the descriptions of Mariappa (1985) in elephant animals such as leopard cat (Rajani et al., 2012) and black foetus which indicated that lobations had not undergone buck (Verma et al., 2015). much structural variations with age. The convex lateral and ventral borders of right lateral lobe constituted an arc. Microscopically, liver had a dense irregular The deep umbilical fissure and its extended round ligament, connective tissue capsule, Glisson’s capsule. Squamous notches on ventral border and gall bladder fossa are the epithelial cells formed the outer serosal covering of the landmarks demarcation of liver into lobes in farm animals capsule. Capsule composed of mainly collagen fibres as (Nickel et al., 1979; Getty, 1985). However, the study of reported by Thakur et al. (2019) in buffalo liver. In addition, elephant liver revealed round ligament attached to the right a few elastic fibres and smooth muscle fibres were also medial lobe which is a deviation from its expected location discernible. Interlobular connective tissue septa of variable 1 2 3 Figs. 1-3 1. Liver of Asian elephant- Parietal view. Db- Dorsal border, Rl- Right lateral lobe, Rm- Right medial lobe, L- Left lobe, Q- Similar to quadrate lobe, C- Coronary ligament, F- Falciform ligament, Ro- Round ligament of liver, Um- Umbilical fissure; 2. Liver- Visceral view. Rl- Right lateral lobe, Rm- Right medial lobe, L- Left lobe, Q- Similar to quadrate lobe, P- Hepatic porta, Lo- Lesser omentum, Ro- Round ligament of liver, Um- Umbilical fissure; 3. Liver- Visceral view showing hepatic porta: LM- Lesser omentum, P- Portal vein, HA- Hepatic artery, B- Bile duct, L- lymph node. thickness originated from the hilus and divided the liver parenchyma into large number of small hepatic lobules. The septa carried intra lobular branches of heatic artery, portal vein and bile duct. Fine reticular fibres were evident within the lobule. The hepatic lobules had irregularly hexagonal outline and were demarcated from adjacent lobules by incomplete, indistinct septa. The collagen fibres of septa were visible only at regions where adjacent lobules 1 2 meet (Fig. 4). Thakur et al. (2019) had also described Figs. 4-5 4. Photomicrograph of liver of Asian elephant: L- Hepatic scanty connective tissue in buffalo liver. The centre of lobule, H- Laminae of hepatocytes, PT- Portal triad, HA- Hepatic artery, PV- Portal vein, B- Bile ductule. H. & E. x 50; each lobule enclosed a prominent thin walled central vein. 5. Photomicrograph of liver of Asian elephant: H- Radiating, irregular, branching and interconnected laminae Hepatocytes, S- Sinusoids, E- endothelial cell, K- Von Kupffer of hepatocytes extended from the central vein to the cells, B- Binucleate cells. H. & E. x 500. 27 Liver Asian Elephant boundary of tubules. The laminae were separated from Mariappa, D. 1985. Anatomy and Histology of the Indian each other by intervening irregular, wide and anastomosing Elephant. Indira Publishing House, Michigan, sinusoids (Fig. 5). Hepatic sinusoids constituted the USA. intralobular system of blood capillaries which carry blood Miller, R.E., and Fowler, M.E. 2015. Fowler’s zoo and wild animal from periphery of the lobule to the central vein. Usually, medicine. Vol 8. Elsevier Saunders. the hepatocyte laminae were single-cell thick. Polyhedral hepatocytes enclosed a centrally placed spherical, vesicular Nickel, R., Schummer, A.