{'fraction_non_alphanumeric': 0.035500690078208864, 'fraction_numerical': 0.03596074221745131, 'mean_word_length': 4.730667838312829, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 1, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Gross and Ultra-Structural Studies on the Large Intestine of Uttara Fowl

Uttara fowl is unique in its adaptation to the agro-climatic conditions of their habitat (Kaur et al., 2010). Their germplasm is unexplored and possess various potential genes responsible for survival in rough conditions of hilly terrain of Uttarakhand. Uttara fowl is mainly found in Kumaon region of Uttarakhand. This breed has evolved through natural selection in indigenous agro-ecological conditions and is well adapted to the local environment. There is very little information available on characteristics of local hill fowl of Uttarakhand. However, existence of different strains of Uttara fowl has been reported (Pant et al., 2007). Uttara fowls have low cholesterol content in their blood which makes it suitable for heart patients and obese people. It has high glucose level in its blood due to more energy requirement at high altitude, more activity and more flying International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 7 Number 03 (2018) Journal homepage: http://www.ijcmas.com


Introduction
Uttara fowl is unique in its adaptation to the agro-climatic conditions of their habitat (Kaur et al., 2010). Their germplasm is unexplored and possess various potential genes responsible for survival in rough conditions of hilly terrain of Uttarakhand. Uttara fowl is mainly found in Kumaon region of Uttarakhand. This breed has evolved through natural selection in indigenous agro-ecological conditions and is well adapted to the local environment. There is very little information available on characteristics of local hill fowl of Uttarakhand. However, existence of different strains of Uttara fowl has been reported (Pant et al., 2007). Uttara fowls have low cholesterol content in their blood which makes it suitable for heart patients and obese people. It has high glucose level in its blood due to more energy requirement at high altitude, more activity and more flying The present study was conducted on 24 Uttara fowl birds. The gross and ultra-structural features with their age-related changes in the large intestine were studied. The length and weight of caeca and colorectum and their diameter and thickness at proximal, middle and distal portions in all the age groups increased with advancing age. The left caeca were slightly longer and heavier than right caecum in all studied age groups. Scanning electron microscopy revealed that the proximal portion of caecum possessed finger like villi with dome shaped tip in day old bird which later showed tapering peak shaped tip. Villi were absent in distal portion of caecum and only folds were observed with wavy pattern bearing goblet pits. Villi in colorectum were tongue shaped with a curved tip and corrugated surface. tendency than commercial birds (Kaur, 2007). Fundamentals for the production performance in a poultry flock are their genetic merit, management and health. The study of avian gastrointestinal tract anatomy is still in its infancy and needs to be further explored as it plays a vital role in feed utilization which ultimately affects the overall productivity of the bird. There are many nutritional reports on the avian intestinal system but very little is known about the detailed anatomy of large intestine (Bayer et al., 1981;Turk, 1982). Different fields of veterinary and animal sciences are dependent on the anatomy and histology of body organs (Argenzio, 1980). The large intestine due to its lympahatic tissue aggregates in the colon and caeca has a major immunological role (Ushakumary et al., 2002). Caecal functioning is still only partly understood (McNab, 1973, Braun andDuke, 1989). However, research of many decades has revealed its role in energy balance and osmoregulation which involves absorption of material from the caecum. Caeca may also serve as the site for several different functions, especially digestion of small food particles, absorption of nutrients, production of immunoglobulins, utilization and absorption of water and metabolism of uric acid into amino acids. Caecotomy has shown to increase the water intake and increased excretion of water in faeces (Son et al., 2000;. Persual of literature revealed limited information pertaining to the large intestine of Uttara fowl. Keeping in view the above consideration, the present study was conducted to study detailed gross morphology, gross morphometry and ultrastructure of large intestine of Uttara fowl.

Experimental birds
To carry out study on structural organization of the large intestine of Uttara fowl, a total of twenty-four birds were purchased from Instructional Poultry Farm, G.B Pant University of Agriculture and Technology, Pantnagar. All the birds were vaccinated against Newcastle disease and Infectious Bursal disease with primary (for both) and booster (for Newcastle disease) doses.

Experimental design
Based on age, the birds were divided into four groups viz. day old, 7, 28 & 112 days old birds with six birds in each age group. On each observation day, six birds were utilized for gross morhometrical features of the large intestine. Two birds were used for ultrastructural investigations.

Gross morphological and morhometric studies
The birds were sacrificed by severing the carotid artery and jugular veins. Feathers were removed manually and the intestine was carefully dissected out. The weight of the various parts of the large intestine was recorded using digital balance (Sartorious, 2014). Thereafter, the caecal length of the bird (right and left), outer diameter of caecum, thickness of caecum wall, inner diameter of caecum, length of colorectum, outer diameter of colorectum, thickness of colorectum wall and inner diameter of colorectum were recorded by using digital vernier calipers (0-150mm).

Ultra-structural studies
Scanning Electron Microscope (SEM) studies was carried out as per standard method at SEM facility GBPUAT Pantnagar. Electron microscopic studies were carried out as per standard method described by Electron microscopic manual of AIIMS, New Delhi, Malorni et al., (1998) and Chauhan (2003) with some modifications and the steps involved were fixation, washing, dehydration, drying, mounting, sputter coating, viewing and photography.

Gross morphology and morphometry
The large intestine of Uttara fowl comprised of a paired, enlarged caeca ( Fig. 1) also reported by Sisson et al., (1953), Clench (1999, Hassouna (2001), Samte (2008), Nasrin et al., (2012), Mahmud et al., (2015). A short straight colorectum was present continuous with the ileum and the cloaca. In the present study the sampling is done from ileo-colic junction to cloaca and there is no differentiation between colon and rectum the term colorectum will be used instead of colon same was reported by Mcleod (1939) and Romanoff (1960) in chicken, Nasrin et al., (2012) in broiler, Mahmud et al., (2015) in Indigenous Nigerian Chicken. While Samte (2008) in Kadaknath fowl and Nickel et al., (1977) in chicken, reported that a short straight colon continuous with the ileum and the cloaca whereas Getty (1975) and Majeed et al., (2009) reported the terminal segment of large intestine as rectum. In present study, the entire caecal length was divided into three main portions: Proximal, Middle and Distal as also reported by Mahmud et al., (2015) in Negerian chicken Nasrin et al., (2012), Hassouna (2001) and Pilz (1937) in chicken. The diameter of both right and left caecum in Uttara fowl was minimum at its base and increases along the length as they run towards the distal portion. However, the wall thickness was more in the proximal portion and decreases along the length caudally. These findings were in accordance with observation of Pilz (1937), Hodges (1974), Hassouna (2001) and Nasrin et al., (2012) in chicken. The caecum was found to be attached to small intestine by two ileocecal ligaments as also reported by Nickel et al., (1977). The enlarged caeca was observed as reported by King and McLelland (1975) Samte (2008) recorded average length of right caecum at day 1, 7, 28 and 112 as 4.52 cm, 6.50, 9.28 and 17.24 cm respectively in Kadaknath fowl. Pilz (1937), Bradley and Grahame (1960), Hodges (1964), King and McLelland (1975), Nickel et al., (1977), Ghosh (1995) and Verma et al., (1998) recorded the length of caeca in 112 days old bird as 14 to 23.5, 16 to 18, 12 to 16, 14 to 23.5, 12 to 25, 15 and 17.2 cms respectively in chicken. The left caeca was slightly longer than corresponding right caeca in all the studied age groups. The average length of left caeca at day 1, 7, 28 and 112 was 3.71±0.163, 6.0±0.12, 9.52±0.26 and 16.84±0.29 cm, respectively (Table 1, Fig. 2). On comparing mean length of right caeca and left caeca in all the age groups it is inferred that the length of left caeca is greater than that of right caeca. Samte (2008) recorded the length of left caecum in Kadaknath fowl at day 1, 7, 28 and 112 as 5.17, 7.0, 10.14 and 17.81 cms respectively which are in line with the present findings that the length of left caecum is slightly greater than corresponding right caecum. The length of left caeca in Uttara fowl birds of all ages were longer than their respective right caeca also correspond to the findings of Ewa Dziala-Szczepanczyk and Katarzyna Betlejewsk (2003) in Black scoter (Melanitta nigra) and Ewa Dziala-Szczepanczyk (2006) in Long tailed ducks. The average length of the colorectum at day 1, 7, 28 and 112 was 2.37±0.13, 3.49±0.12, 4.22±0.21 and 7.12±0.10 cm respectively (Table 1, Fig. 2) which is very close and in accordance with the findings of Samte (2008) in Kadaknath fowl who recorded average length of the colon at day 1, 7, 28 and 112 as 2.37, 3.42, 4.22 and 7.11 cm respectively. In chicken, Nasrin et al., (2012) reported that the colorectum was the terminal part of the intestine, passing between the ileo-cecal junction and the cloaca. It was comparatively short and straight and had thick, muscular walls. The average length of colorectum being 2.925±0.119, 6.82±0.011 and 8.83±0.037 cms at day1, 14 and 28 respectively. The colorectum of Uttara fowl was short and nearly straight lying ventral to the vertebrae leading from the ileocaecal junction to the cloaca. The length of the colorectum in adult Uttara fowl bird observed is similar with that of Pilz (1937), Hodges (1974), Nickel et al., (1977) and Verma et al., (1998) in adult fowl where the length were reported to be 8 to 11 cm, 8 cm, 8 to 11 cm and 7 to 8 cm, respectively.

Ultra-structural studies
SEM examination of proximal caecum in day old Uttara fowl bird revealed that villi were uniformly finger shaped (Fig. 6). This corresponds to the shape of duodenal villi in white leghorn as described by Kalita (2009) in Kadaknath fowl. Villi showed a dome shaped tip. Surface was not smooth and showed crevices throughout the surface and horizontal recesses were quite prominent. In distal caecal portion of day old bird, villi were absent and only mucosal folds with wavy appearance were present. Surface was diffusely corrugated with no distinguishable structure. Many goblet cell pores were present throughout the surface ( Fig. 7 and 8).
SEM Studies in colorectum of day old bird revealed that most of the villi were tongue like shape with curved tip. Hexagonal cell outlines were observed on higher magnification. These findings are in accordance with findings of Kalita (2009) in ileum of Kadaknath fowl. SEM studies in proximal caecum of 112 day old bird revealed the growth in size and horizontal recesses disappeared and surface became corrugated with many goblet cell pits. These findings are contrary to findings of Kalita (2009) in duodenum and jejunum who reported plate like villi. Tips of villi from dome shape changed to a tapering peak like shape. On the apical surface epithelial cell clusters were quite prominent. Distal Caecum in 112 day old revealed a rough surface which may be due to the extrusion of epithelial surface imparting a honey comb like structure. Colorectum villi in 112 day old bird increased in size but there were no distinct change in their morphology from day old bird. The villi were tongue shaped with curved tip (Fig. 9).
The present study showed that the large intestine of Uttara fowl comprised of a pair of well-developed caeca starting from ileocolic junction which were blind pouches extending along the line of small intestine towards liver cranially. Colorectum was short tube starting from ileocecocolic junction to cloaca. Length of caecum and colorectum increased significantly with increasing age. Length and weight of left caecum was found slightly greater than right caecum in corresponding age groups. Scanning electron microscopy revealed that the villi were finger shaped with the tip as dome shaped in older birds in the proximal portion of caecum. However, the tip of the villi became tapered later. Goblet pits were found in the distal portion of caecum. The villi were tongue shaped in colorectum and had corrugated surface.