Does a non-invasive method of castration affect haemato-biochemical indices in domestic piglets?

Introduction

Pig rearing has been recognized as one of the most profitable ventures among the tribal community of India. One of the most efficient feed converting animals among all domesticated livestock species is pig, which plays a pivotal role in improving the socioeconomic status of the tribal masses and weaker sections of the society. Efficiency of the pigs is recorded to as twice that of ruminants (Mpofu and Makuza, 2003) [12] . As compared to other livestock species, pig has a great potential to contribute to faster economic return to the farmers, because of certain inherent traits like high fecundity, better feed conversion efficiency, prolificacy, early maturity, short generation interval and excellent dressing percentage. Pig production has largely remained under backyard system of rearing with the backward sections of the society. It appeared as potential source of animal protein and avenue for additional income and employment that can improve the livelihood in a sustainable manner (Petrus et al., 2011) [14] . Due to remoteness and inaccessibility, even the rural hill farmers have evolved a self-sustainable local resource-based production system, in which pigs are mainly dependent on local vegetation, crop residues and kitchen waste (Kumaresan et al., 2007; Moanaro et al., 2011) [8,11] . Castration is one of the most important management activities of the farm in pig husbandry. At present, surgical castration seems to be the only method of castration in pig. Though surgical castration is widely practiced over a long period of time, it required technical expertise, necessary facilities, expenses and post-operative care. The history of surgical castration of male pig dates back to 3000-4000 BC. It is practiced primarily to avoid boar taint (unwanted odour) to prevent skatole and androsterone accumulation in fat which is an unpleasant odour in meat of an un-castrated male pig and is a carcass quality concern. However, surgical castration is a painful procedure although this pain can be reduced with the use of analgesics (McGlone and Hellman, 1988; White et al., 1995) [10,15] , also induces oxidative stress in the blood of animals (Abou-Khalil et al., 2020) [1] . On the other hand, non-invasive method of castration gained the momentum in recent times due to welfare issues with open method castration. Non-surgical chemical castration has a positive impact on feed conversion and consequently, on the environment. It is cost effective, and animals return to normal physical activities easily, a small number of persons are required to perform this procedure, and more preferred than other methods of castration (Capucille et al., 2002; Cavalieri, 2017; Hassan and Fromsa, 2017) [2,3,4] . It was hypothesized that chemical castration would not affect the haemato-biochemical variables in piglets due to painless method of orchiectomy. Hence, the present study was undertaken to compare the effect of chemical castration with surgical method on blood variables of Ghungroo piglets.

Materials and Methods 1. Experimental design, animals and management

Twenty (n=20) healthy indigenous Ghungroo male piglets (Sus domesticus) weighing on an average 4.5±2 kg and aged around 1-2 months were used for the study. The piglets were maintained under standard feeding and management of the farm. The experimental animals were randomly divided into four groups. Each group contained five (n=5) clinically healthy piglets. Every animal in each treatment group (T 1 , T 2, T 3 ) was administered a single bilateral intratesticular injection of potassium permanganate solution of three different concentrations for a volume of 1ml per testis (T 1 =0.25 g, T 2 =0.20 g and T 3 = 0.15 g whereas control group is denoted as T 0 ). Each intratesticular injection was performed using a sterile 21-gauge needle inserted from the caudoventral aspect of each testis approximately 1 cm from the epididymal tail directed towards the dorso-cranial aspect of that testis. The solution was deposited carefully in a withdrawing fashion over entire route by linear infiltration from proximal end to the distal end. The small area to be injected at the bottom of each testis was cleaned with Betadine® solution 5% (Povidone iodine) before every injection. Necessary measures were taken to avoid seepage of the solution from the injection site. Following injection, the animals were kept under normal routine observation.

Collection of blood samples and analysis

Blood samples were collected from the experimental animals on the 2 nd day post-injection of chemical and surgery. A 5ml disposable syringe (DispoVan®) and 20gauge needle was used to collect blood from the anterior venacava of the experimental animals. The collected blood samples were immediately transferred into a sterile glass tube and allowed to stand in tilted position for 2-3 hours for separation of serum. The serum samples were kept at -20 °C in deep freezer until assayed. All the analysis was done at the laboratory with the help of standard protocol for each sample of different variables.

Statistical analysis

All the data were collected, stored and processed in Microsoft excel. The data were analysed with the help of IBM SPSS software 26.0 version. The data was analysed using two ANOVA. Means having significant differences were subjected to post-hoc comparisons (Duncan's multiple range test) and considered as significantly different when p<0.05.

Results and Discussion

The effect of male pig chemical castration on hematological variables has been scarcely investigated. In the current trial, no impact of it was detected on packed cell volume, total protein, blood urea nitrogen except serum cortisol (Table 1). The present result would suggest that orchiectomy with open method increases cortisol, thereby enhancing stress level which hamper animal welfare and performance. Mean packed cell volume of different treatment groups were recorded as 37.14±5.90, 39.15±4.60, 44.73±3.10 and 29.29±5.20 respectively. All the treatment groups did not differ significantly; however, increased values were recorded in T 2 group followed by T 1 , C0 and T 3 . The present findings are in conformity with the study conducted by several researchers (King et al. 1991; Kang et al. 1993; Neto et al. 2014) [7,6,13] . Mean total protein values were 7.25±0.48, 7.13±0.48, 7.32±0.89 and 7.17±0.62 respectively. The result showed no significant difference among all the groups. There were no alterations in total protein concentrations in any of the treated groups with respect to the control group as well as among the three treated groups (p<0.05). This is in agreement with the study of Jana et al. (2007) [5] . Type of castration did not elevate certain blood parameters in domestic animals due to orchiectomy. Mean blood urea nitrogen of control, T 1 , T 2 and T 3 groups were recorded as 18.80±1.93, 23.20±2.63, 20.20±1.32 and 19.20±1.71 respectively. The study revealed that there was increase in the concentration of BUN among T 1 , T 2 and T 3 than control group but the values were under normal physiological range.

Serum cortisol level revealed that there was a slight increase of concentration in T 1 group as compared to other treatment groups. The mean values of control, T 1 , T 2 and T 3 were 8.38±0.40, 7.20±0.49, 7.01±0.17 and 6.95±0.10 respectively. All the values are under normal physiological range. This study is in accordance with King et al. (1991) [7] and Lessard et al. (2002) [9] . The stress indicators including concentrations of Packed cell volume (PCV), total protein, Blood urea nitrogen (BUN) and Serum cortisol were measured to ascertain whether a single intratesticular injection of potassium permanganate was associated with any chronic stress response in the experimental animals. Table 1 showed that there were no significant differences among all the treatment groups.

Similarly, King et al. (1991) [7] have suggested that serum cortisol concentration following chemical castration may be minimal and is less than the surgical castration.

Conclusion

Chemical castration has proven itself as a safe and alternative to surgical castration in pig. The present study reveals that intratesticular injection of potassium permanganate in Ghungroo piglet rendered them sterile. It has no effect no haemato-biochemical variables viz. packed cell volume, blood urea nitrogen and total protein except serum cortisol level. The study also showed there is considerable stress to piglets castrated surgically, whereas chemically castrated piglets suffered minimal pain and stress. It can be recommended that chemical castration acts as an effective and alternative method to open technique.

Acknowledgement

AcknowledgementThe authors are thankful to Vice-chancellor and Dean, West Bengal University of Animal and Fishery Sciences, Kolkata and Head, ERS-IVRI, Kolkata for necessary support for the research work.

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