Effect of supplementation of differentially treated banana inflorescence on intestinal morphology in broiler birds #

Effect of supplementation of differentially treated banana inflorescence on intestinal morphology in broiler birds

Poultry farming is currently one of the fast-growing subsector of livestock industry and the increasing growth necessitates the adoption of feed additives which are cost effective, safe and improve production efficiency. The use of antibiotics as feed additive is often being questioned due to issues regarding antimicrobial resistance and antimicrobial residues in food animals. The use of prebiotics and probiotics are gaining more importance as natural establishment of probiotic organism ensures gut health and improves gut immunity.
Banana is the biggest herbaceous and tropical flowering plant in the family Musaceae and is one of the earliest cultivated plants (Perrier et al., 2011). The male sterile flower of the banana plant is the banana blossom, flower, heart, or bud (Suffi et al., 2021) and found to have health benefits such as the antioxidant and anti-diabetic activities (Lau et al., 2020) and contains numerous distinct bioactive components including phenols, tannins, steroids, glycosides, flavonoids, and saponins (Pushpaveni et al., 2019). Banana inflorescences possess 8. 21, 14.50, 4.04, and 20.6 percent protein, fat, ash, and hemicellulose on dry matter basis, respectively. The percentage of total carbohydrates reported was 58.82. Due to their high potassium content (5008.26 mg/100g) and fibre content (49.83%), the dried inflorescences were shown to provide a significant nutritional complement (Fingolo et al., 2012).
The current study aims at understanding the effect of differentially treated banana inflorescence on gut health, intestinal weight and morphometry in poultry broilers.

Materials and methods
Ninety-six, day old Vencobb 430 broiler chicks were raised under standard farm conditions at Instructional Livestock Farm Complex (ILFC), College of Veterinary and Animal Sciences, Pookode, Wayanad for the experimental study. All the chicks were wing banded, weighed individually and were randomly distributed into three groups (T1, T2, and T3) with four replicates having eight chicks each. Banana inflorescence (Musa AB) were procured and dried in the oven at 100°C for 42h and powdered. The steam treated inflorescence was prepared by autoclaving the whole banana inflorescence (Musa AB) at 121°C for 20 minutes. The basal diets (broiler pre starter, starter and finisher) were prepared as per BIS (IS 1374(IS : 2007 and fed to T1 as control. For the other groups, the basal diets were supplemented with dried banana inflorescence (T2) or steam treated banana inflorescence (T3) at 5g/kg respectively. The composition of the basal diet (pre-starter, starter and finisher) and levels of supplementation followed in this study are presented in Table 1 & 2.
The birds were reared for 42 days under standard brooding, housing and management practices followed in the farm and were given pre-starter (0-7 days), starter (8-21 days) and finisher (22-42 days) feed and clean drinking water ad libitum.
On the 42 nd day of feeding trial, two birds from each replicate were randomly selected and humanely sacrificed to assess the intestinal weight and histomorphometry. The weight of intestine and pH were assessed in one bird and the histo-morphometric measurements of gut were assessed in the other bird. After slaughter, the bird intestine was collected, weighed and flushed slowly with normal saline to remove any feed that may be present in the intestine and was placed in 10 % neutral buffer formalin for 7 days. After seven days the 0.5 cm long tissue was cut from duodenum, jejunum, ileum and caecum, placed in cassette and processed by standard tissue processing protocols (Luna, 1968). Sections were taken at 5μm thickness by using semi-automatic M-TECH microtome. Haematoxylin and Eosin staining method table 1. Level of supplementation of feed

Result and discussion
At the end of the 42-day trial, the live weight obtained among the three groups were 1533.5 ± 18.79,1659.38 ± 7.8 and 1711.63 ± 20.9 g, respectively. The live weight, intestinal weight, per cent of intestine and the pH of ileum and caecum are given in Table 3. The group supplemented with steamed banana inflorescence and dried banana inflorescence showed significant (p<0.01) increase in live weight. The per cent carcass yield obtained in the three treatment groups were 70.42 ± 0.18, 71.7±0.15, 71.81±18, respectively, also varied significantly (p<0.01) with the treatments and the highest carcass yield recorded was with the stream treated banana inflorescence supplemented group. The observations were found to be similar to the dressing per cent of 70.47, 70.90 and 72.28 reported by Waqas et al. (2018) with the supplementation of mannan oligosaccharide (Actigen™) at 0.2, 0.4, 0.6 g/ kg, respectively when compared to the control (69.91 %). In contrast to our findings, Shajini et al. (2022) reported supplementation of chitosan at 30g/kg to birds did not have any significant effect on dressing percentage.
The weight of intestine were 141.88 ± 6.37, 178.75 ± 8.36 and 175 ± 7.84 grams respectively, found to be significantly (p<0.001) increased with the supplementation, while the per cent of intestine with respect to carcass weight were 14.3±.007, 15±0.006 and 14±0.007 respectively, were found to be similar among the treatment groups. Wang et al. (2016) also reported no difference in per cent intestine (2.622) on supplementation of prebiotic (mannan oligosaccharide) when compared to control (2.521).
The pH values in ileum and caecum of three treatment groups were 6.18 ± 0.21, 6.44 ± 0.26, 6.39 ± 0.04 and 6.83 ± 0.21, 6.71 ± 0.32, 6.87 ± 0.12 respectively (Table 3) and values did not vary significantly. The findings of present study were similar to Houshmand et al. (2011) who reported that the feeding of prebiotic feed did not affect the pH of ileum (6.63) and caecum (6.93) of birds.
The intestinal villi continuously adjust as a response to conditions in the lumen of the intestine (that is influenced by composition of diet) reflecting the dynamic environment inside the intestine of animals. Accordingly, longer intestinal villi are associated with an increase in the absorptive surface of the intestines as well as increased absorption capacity (Izadi et al., 2013). Analysis of intestinal morphometry revealed a significant increment in villus height in all banana inflorescence supplemented groups. This increment indicated an increase in intestinal surface area and absorptive strength. The villus height of duodenum was significantly  (Fig.1). There was also significant increase in duodenal crypt depth ratio in banana inflorescence supplemented group suggestive of increased lactic acid bacteria (Nguyen et al., 2021). Pelicano et al. (2005) reported a lower (p<0.01) villus height in the duodenum of birds fed diets with prebiotics (1401 μm) than control (1539 μm.) Similar observations with improved villus height, crypt depth and villus-to-crypt ratio of duodenum were made by Eyng et al. (2014) in birds that were fed bee pollen or propolis and Supriya et al. (2022) in birds fed with probiotics and organic acids.
The caecal villus height showed significant difference (p<0.001) among the treatments and were highest in T3 (1124.35 μm) when compared to control (559.08 μm) and T2 (370.81 μm). Tsirtsikos et al. (2012) also observed significant increase in villus height (249,223,272) in caecum when compared to control (204) when supplemented with probiotic, Lactobacillus reuteri at 10 8 , 10 9 , 10 10 colony forming units of probiotic/kg. According to Iji and Tivey (1998), the increase in villus height and crypt depth may be due increase in bacterial colonisation which increase the fermentation rate and absorption of nutrients.

conclusion
In the present study, supplementation of banana inflorescence in dried or steam treated forms, the dried form at 0.5 percent level in broiler diet could significantly increase the live weight in broiler diet and the histomorphometric parameters in gut significantly varied with the control. Birds having steam treated banana inflorescence supplementation, showed increased villus height of duodenum, jejunum and caecum and increased crypt depth in jejunum, ileum and caecum as well as duodenal and caecal villus to crypt depth ratio, while treatment with dried banana inflorescence showed highest duodenal crypt depth, ileal villus height and crypt depth ratio which could help in better nutrient absorption and growth in broiler birds.