Influence of dietary supplementation of microencapsulated essential oils on nutrient digestibility, plane of nutrition and haemato-biochemical parameters of growing goats

Introduction

The use of essential oils in ruminant diets as an alternative to antimicrobials agent, rumen fermentation modifiers, greenhouse gas emissions reduction agent, and improved animal productivity has been documented in various studies (Zeng et al., 2015; Oh et al., 2017) [9,5] . Essential oils provide beneficial effects on immune response, gut health, antioxidant status and blood cholesterol in broiler chickens (Chowdhury et al., 2018) [3] . Encapsulated essential oils can reduce harmful bacteria and promote digestive enzyme activity and higher concentrations of short chain fatty acids in broiler chicken (Yang et al., 2019) [7] . Some studies showed improvement in growth performance, nutrient digestibility, increase Ig G concentration and decrease noxious gas concentration in weanling piglets (Cho and Kim., 2015) [2] . However, EOs are volatiles, heat sensitive, and susceptible to oxidation in the presence of light, air and moisture that hinder their application. Thus, microencapsulation is one strategy employed to prolong the stability of EOs during manufacturing, processing, and storage of feed. Spray drying is one of the oldest encapsulation methods that has been used since 1930s to prepare the first flavour compounds encapsulated. This method is the most used in food industry due to its cost of manufacturing, varieties of encapsulating matrices, adequate retention and stability of volatiles compounds, and large scale production in a continuous mode. Keeping in view advantages of inclusion of essential oil in livestock ration the present study was designed to assess the effect of supplementation of microencapsulated essential oils on nutrient digestibility, plane of nutrition and haemato-biochemical parameters of growing goats.

Materials and Methods

The animal experimentation protocol was approved (No. IV/21) by the Institutional Animal Ethics Committee (IAEC) of College of Veterinary and Animal Sciences, Udgir. The trial was conducted at Livestock Farm Complex, College of Veterinary and Animal Sciences, Udgir, Maharashtra, having latitude 18.3942886, longitude 77.1176 and altitude 2086 ft. During the trial period, maximum 30 °C and minimum 24 °C temperature and 823 mm precipitation was recorded. The trial involved eighteen Osmanabadi growing goats of 4-5 months age (9.80-9.83 kg) which were randomly divided into three equal groups viz. T0, T1 and T2, having six goats of either sex in each group. Group T0 was fed concentrate mixture routinely used on farm whereas group T1 and T2 were fed same concentrate mixture and supplemented with microencapsulated essential oils (EOM) @ 1 and 1.5 g/animal, respectively, for seven consecutive days with 23 days interval after every supplementation for entire experimental period of 90 days. All experimental animals were fed on DHN6 as a source of green roughage throughout experiment. The trial was conducted for a period of 90 days.

Microencapsulated Essential oils

The essential oil containing monoterpene and diterpene compounds, microencapsulated with palmitic acid by using air dry methods was utilized for supplementing growing goats from treatments groups. The essential oil was present in free flowing granular powder form having yellow colour, easy to mix homogenously in concentrate mixture. Experimental growing goats were fed under stall feeding system with commonly routine managemental practices. The amount of concentrate mixture and roughage feeding was adjusted according to change in body weight and growth rate of growing goats. Animals were offered a diet consisting of concentrate mixture and green fodder to meet their nutrient requirements (ICAR, 1998) [4] . The growing goats were fed allowance of concentrate mixture at 8:00 am and 3.00 pm while green roughage (DHN6) was made available throughout day. Feed left over weighed next day morning to calculate total dry matter intake. All the growing goats were treated with standard anthelminthic protocol before starting of the experiment to ensure that growing goats were free of parasites. All the experimental growing goats were reared in intensive housing system-zero grazing stall feeding with in a well-ventilated house with common routine managemental practices and environmental conditions. The experimental growing goats were housed in three separate compartments. Ad-libitum fresh, clean, and cool drinking water was provided to growing goats throughout experimental periods. In the last week of the experiment a digestibility trial of seven days duration was conducted by total collection method. All the growing goats from each group were used for the digestibility trial. The representative samples of concentrate mixtures and green fodder (DHN6) used for feeding of experimental growing goats were collected at fortnight interval throughout the experimental period, oven dried and the pooled samples were analyzed. The fecal samples obtained while conducting digestibility trial were also analyzed. The analysis for proximate principles was undertaken as per AOAC (2005) [1] in the laboratory of Department of Animal Nutrition, College of Veterinary and Animal Sciences, Udgir. Blood samples were obtained from all growing goats from each treatment groups at the end of research trial i.e. on the 90 th day, four ml of blood was drawn from the jugular vein of all experimental growing goats in to the syringe and 1 ml blood was transferred in to vacuum tubes containing potassium salt of ethylene di amine tetra acetate (EDTA). The samples added with EDTA were the analyzed for Hb, RBC count with the help of blood analyzer. The biochemical estimations of blood serum were determined calorimetrically, using commercial kits (Erba Mannheim) with the help of biochemical analyzer. The individual serum samples were analyzed for total serum total protein, serum albumin, serum globulin, and serum glucose. The methodology and the set of reagents used in respect of each parameter were as per the recommendations of the manufacturer of the analyzer system. Observations of various parameters recorded during experimental period were tabulated and data were statistically analyzed as per Snedecor and Cochran (1994) [6] , by using Randomized block design and Completely Randomized Design.

Results and Discussion

The percent ingredient composition of concentrate mixture used in present experiment is presented in Table 1. The chemical composition (% DMB) experimental of concentrate mixture and DHN6 is presented in Table 2. The overall performance of growing goats from various experimental groups is presented in Table 3. The average DMI of group T2 was significantly (p < 0.05) higher than control, however, difference between group T2 and T1 was non-significant. The average percent DMI and DMI per unit metabolic body size was comparable among all the experimental groups. This also indicated that supplementation of microencapsulated essential oil had no adverse effect on palatability of feed. These results corroborated with the findings of Yatoo et al. (2018) [8] who observed increase in DM intake of growing buffaloes by the supplementing blend essential oils at 0.15 and 0.30 ml/kg of dry matter intake. The average TDN intake of group T1 and T2 was significantly (p < 0.01) higher than group T0, however, difference between group T1 and T2 was non-significant. The average DCP intake of growing goats from group T2 was significantly (p < 0.01) higher than group T1 and T0, however, average DCP intake of group T1 was significantly (p < 0.01) higher than group T0. Average RBC and Hb count, serum total protein, globulin, albumin and glucose values of microencapsulated essential oil

supplemented groups T1 and T2 were numerically higher than control group, however, between essential oil supplemented groups it was higher in group T2 than group T1. However, all these blood haematological and biochemical parameters revealed no significant difference among various experimental groups. At the end of the experiment, the digestibility trial of seven days was conducted by total collection method. The results of the same are presented in Table 4. The average digestibility coefficients for DM, OM and EE were significantly (p < 0.01) higher in groups T2 than group T1 and To, however, between group T1 and To, it was significantly higher for group T1. The average digestibility coefficients for CP and NFE were significantly (p < 0.05) higher for group T1 and T2, however, difference between group T1 and T2 was nonsignificant, although it was numerically higher in group T2.

Conclusion

From the result obtained under the present study, it is concluded that supplementation of microencapsulated essential oils @ 1.5 g/growing goat for seven consecutive days in a month for 3 months period is beneficial for improving nutrient intake, digestibility of nutrients and improved serum biochemical and haematological parameters. The supplementation of microencapsulated essential oils @ 1 g/growing goat is also beneficial in growing goats.

Acknowledgement

AcknowledgementWe thank the Central Breeding Farm, College of Veterinary and Animal Sciences, Udgir, Latur-413517, M.S., India for providing animals and necessary facilities for carrying out this research work.

References

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