Azolla based complete feed block on growth, nutrient utilisation and blood biochemicals of Beetal X Assam hill goat kids

Introduction

Azolla (Azolla pinnata) an unconventional feed of livestock, increases the feed consumption and digestibility by increasing the amount of nutrients that animals absorb from the ration. Due to its high protein, essential amino acids, vitamins, growth-promoting intermediary, and mineral content, it can be recognised as an excellent livestock feed. Due to its high palatability, availability, and high yield, Azolla pinnata may serve as a substitute for concentrate, green fodder, and as a supplement to diets high in protein. It is acknowledged as the most affordable and plentiful source of protein due to its capacity to synthesize amino acids from a variety of practically limitless and easily accessible primary materials. It contains several essential amino acids, carbohydrates (34.90%), fat (3.10%), protein (20.00-25.50%) and 8.50-10.70 percent cellulose (Sithara and Kamalaveni, 2008) [10] . Hence, incorporating low-cost, unconventional feed ingredients like Azolla in feed blocks will definitely reduce the cost of feeding while achieving better growth performance. Considering the nutritional and beneficial effects of Azolla, the present experiment was conducted to investigate the impact of feeding different levels of Azolla-based Complete Feed Block on the growth, nutrient utilisation, and blood biochemical parameters of Beetal x Assam Hill Goats.

Materials and Methods

Twenty-four (24) numbers of growing kids (Beetal x Assam Hill Goat) of 3-4 months of age were divided into four (4) groups (T 0, T 1 ,T 2 ,T 3 ) consisting of 6 kids in each having same numbers of male or female in each group based on similarity in their average body weight in a randomized block design. In the control group (T 0 ), the Complete Feed Block consisted of Napier grass and concentrate mixture at a 60:40 ratio on DM basis. In the group T 1 , T 2, and T 3, the concentrate mixture of Complete Feed Block was incorporated with dried Azolla at 10, 20 and 30 percent levels, respectively, along with the same level of Napier grass as in the control group (Table 1) The feeding trial was conducted for a period of 84 days. The blood sample was collected fortnightly up to 84 days in a clot activator vial, and the serum was separated by centrifugation at 2000×g for 5 minutes. The total serum protein, total serum albumin, and gamma-glutamyl transpeptidase (GGT) were estimated as per the procedure mentioned in a commercially available kit. To evaluate the humoral immune response, the Salmonella Typhimurium inactivated antigen (10 9 CFU/per animal) was inoculated during 4 th fortnight. Two doses of antigen were injected intramuscularly to each kid, and the booster dose was inoculated after one week. Blood was collected before and after the antigen inoculation and serum was separated. After that standard protocol for ELISA was followed and OD was read at 492 nm in ELISA reader.

Results and Discussion: Growth performance

In the present experiment, the dry matter intake was significantly higher (p<0.01) in group T 1 followed by group T 0 , T 2 and T 3 (Table2). Shital et al. (2011) observed in Osmanabadi kids that the average daily dry matter intake per kid was higher when concentrate was replaced by 15 percent level of Azolla without any adverse effect. Significantly higher (p<0.01) average daily gain (g/d) and total gain in body weight (kg) was observed in group T 1 , followed by T 0 , T 2 and T 3 , which might be due to the higher intake of DM, DCP and TDN by group T 1 . Roy et al. (2016) [7] reported a higher growth rate in Haryana heifers when concentrate mixture was replaced by 5 percent level of Azolla pinnata. Sihag et al. (2018) [8] also observed significantly higher average daily gain in kids fed with TMR by replacing concentrate mixture at 10 percent level with Azolla. Significantly (p<0.01) better FCE was observed in group T 1, followed by group T 0 , T 2 and T 3 . The better FCE in group T 1 where 10 percent level of Azolla was incorporated, might be due to better body weight gain compared to group T 0 , T 2 and T 3 . Similar findings were also reported by Sihag et al.

(2018) [8] , who observed significantly better FCR in kids fed with TMR by replacing concentrate mixture at 10 percent level with Azolla.

Nutrient Digestibility

The dry matter digestibility decreased with increasing level of Azolla in the diet (Table 3). This might be due to the increasing lignin content in the diet and occurrence of diarrhea (Tamang and Samanta, 1993) [11] amongst the experimental kids fed on Complete Feed Block containing higher level of Azolla. Ghodake et al. (2012) [2] reported significant difference in digestibility coefficient of dry matter in Osmanabadi kids. Sihag et al. (2018) [8] observed significant difference in digestibility coefficient of OM in kids. The digestibility coefficient of CP decreased with increasing level of Azolla in group T 2 and T 3 . This might be due to binding of protein with lignin and silica content of Azolla (Navanath, 2007) [5] . Similar findings were also reported by Kumari (2018) [4] who observed significantly higher CP digestibility in Black Bengal Cross kids fed with 20 percent Azolla-supplemented concentrate mixture.

Although there was no significant difference (p>0.05) between the groups, but numerically higher digestibility of CF was recorded in group T 1 followed by group T 0 , T 2 and T 3 . Significantly higher (p<0.01) digestibility coefficient of NFE was seen in group T 1 and lowest in T 3 .

Blood biochemical profile

The fortnightly average value of total serum protein (g/dl), total Serum Albumin (g/dl), gamma glutamyl transpeptidase (U/L) has been presented in Figure 1. No significant difference was observed in the level of total serum protein between the groups. The values were well within the normal range (6.2-7.9 g/dl), indicating that there was no detrimental effect of feeding Azolla at various levels to the experimental kids. Similar findings were reported by Kumar et al. (2015) [3] , who observed no significant (p>0.05) effect of replacement of concentrate mixture with sun dried Azolla at 25 percent level in Barbari goats. Roy et al. (2016) [7] also observed no significant difference (p>0.05) in total serum protein level in different groups of Hariana heifer fed with concentrate mixture replaced with 5 percent level of Azolla. In case of total serum albumin, statistical analysis showed significant difference (p<0.05) between the groups. Although, the significant difference (p<0.05) was observed at 2 nd fortnight in group T 1 and T 2 ; and at 4 th fortnight between group T 2 and T 0 , all the values of total serum albumin were observed within the normal range (2.9-4.3 g/dl) indicating that there was no detrimental effect of feeding Azolla at various levels to the experimental kids. However, it was observed that there was significant lowering of serum albumin in the T 2 and T 3 groups compared to control group on 2 nd and 4 th fortnight that could be due to slight negative impact of Azolla at 20 and 30 percent level on liver function thereby impacting the growth rates in T 2 and T 3 groups. The serum gamma glutamyl transpeptidase (U/L), showed no significant difference between the groups. All the values of GGT were within the normal range (0-30 U/L) indicating that there was no detrimental effect of feeding Azolla to liver function at various levels to the experimental kids. The findings were in accordance with Reddy et al. (2011) [6] .

Although there was significant decrease of serum albumin in T 2 and T 3 groups, there was no effect on serum GGT that could be due to fact that there was no significant liver damage by the Azolla.

Humoral immune response upon inoculation bacterin

Salmonella typhimurium antigen

The average OD value of ELISA in group T 0, T 1 , T 2 and T 3 were 0.39±0.06, 0.69±0.10, 0.43±0.10 and 0.55±0.11 respectively. Statistical analysis showed there was no significant difference (p>0.05) between the groups suggesting Azolla incorporation in the complete feed block at 10, 20 and 30 percent level have no effect on the immune response.

Cost of Feeding

In the present experiment, the highest and lowest feed cost per kg body weight gain was observed in group T 3 and T 1, respectively. It is due to the highest and lowest body weight gain by the kids of group T 1 and T 3, respectively. highest profit over control was observed in group T 1, indicating that dried Azolla incorporation up to 10% level in CFB is economically beneficial with higher growth performance in kids. Similar findings were also observed by Ghodake et al. (2012) [2] , who reported economically beneficial feeding of kids with incorporation of 15% Azolla in the concentrate feed. Ahmed et al. (2016) [1] observed significant difference (p<0.05) between the groups on feeding 6, 12, 18 and 24 percent Azolla replacing with 25, 50, 75 and 100 percent linseed cake respectively. Significantly lower cost of feeding was observed in group fed with 6% Azolla. Sihag et al. (2018) [8] reported net saving of Rs. 7.90 per kg weight gain for feed cost of crossbred kids when feeding Azolla at 10% level on replacement of concentrate feed.

Conclusion

The present study revealed that, dried Azolla can be incorporated at 10 percent level in concentrate mixture of Complete Feed Block of Beetal x Assam Hill Goat kids with a distinct economic advantage without any adverse effect.

References

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