Haematological and serum biochemical reference values of healthy Agoutis (Dasyprocta leporina) reared intensively in Trinidad, Republic of Trinidad and Tobago

Kegan Romelle Jones, Kavita Ranjeeta Lall and Gary Wayne Garcia

The Open Tropical Forage-Animal Production Laboratory [OTF-APL], Department of Food Production [DFP], Faculty of Food and Agriculture [FFA], The University of the West Indies [UWI], St Augustine, Trinidad and Tobago.
keganjones11@gmail.com

Abstract

The agouti is a neo-tropical rodent that has the potential for domestication. At present it is reared in captivity and hunted for meat. Little information is known on some aspects of the agouti. This study investigated the haematological and biochemical values of ten (10) adult male captive-reared agoutis (Dasyprocta leporina) at the Sugarcane Feeds Centre (SFC) in the Republic of Trinidad and Tobago. Animals had a mean (±SD) weight of 2.34±0.25 kg and exhibited a body condition of 3/5 with no history of illness. The mean values of the haematological parameters were: Red blood cells (RBC) 8.55±0.79x10¹²/l, haemoglobin (HGB) 16.92±2.13g/dl, haematocrit 52.97±5.62%, mean corpuscular volume (MCV) 62.50±3.13, mean corpuscular haemoglobin (MCH) 19.75±1.00pg, mean corpuscular haemoglobin concentration (MCHC) 31.91±1.00 g/dl, red cell distribution width (RDW_C) 16.06±0.87%, RDW_S 37.89±2.63 fl, platelets (PLT) 178.9±112.85x 10⁹/l, mean platelet volume (MPV) 9.43±0.84fl, Plateletcretin (PCT) 0.13±0.08%, Platelet distribution width (PDW_C) 31.74±3.15%, PDW_S 10.13±2.84 fl. White blood cells (WBC) 12.15±3.89 x 10⁹/l, lymphocytes (LYM) 2.08±0.96 x 10⁹/l, monocytes (MON) 0.58±0.34 x 10⁹/l, eosinophils (EOS) 0.00±0.00 x 10⁹/l, basophils (BAS) 0.00±0.00 x 10⁹/l, lymphocytes (LYM) 19.02±10.71%, monocytes (MON) 4.76±2.38% and neutrophils (NEU) 76.19±11.60. Biochemical parameter results were: alkaline phosphatase (ALP) 129.7±47.22 U/l, alanine aminotransferase (ALT) 46.8 ±42.89 U/l, amylase (AMY) 707.00±208.73 U/l, total bilirubin (TBIL) 0.39±0.05 mg/dl, blood urea nitrogen (BUN) 6.60±2.83 mg/dl, calcium (CA) 10.40±1.68 mg/dl, phosphorus (PHOS) 7.48±1.20 mg/dl, creatinine (CREA) 1.10±0.40 mg/dl, glucose (GLU) 170.3±29.57 mg/dl, sodium (NA) 145.00±4.76 mmol/l, potassium (K) 8.20±0.10 mmol/l, total protein (TP) 5.99±0.30 g/dl, albumin (ALB) 5.65±0.25 g/dl, globulin (GLOB) 0.04±0.05 g/dl. No blood parasites were found in the animals sampled. Blood and serum biochemical data gave similar results to other studies done in Dasyprocta spp. in other countries where animals were reared in captivity even though some animals had parasitic gastrointestinal infestation. To the authors’ knowledge this is the first document that recorded the blood values of captive reared agoutis in the Republic of Trinidad and Tobago. The information obtained can be used as references for captive reared male agoutis in the Republic of Trinidad and Tobago.

Key words: hemogram, haemoglobin, haematocrit, mean corpuscular volume, platelets, and lymphocytes

Introduction

The Agouti is a Neo-tropical rodent that is intensively reared by wildlife farmers in the tropical environment of Trinidad and Tobago for its meat. It is one of the few neo-tropical animals that have the potential for domestication (Brown-Uddenberg et al 2004). It is considered as ‘mini-livestock’, a concept which was coined for indigenous livestock that can be used in rural communities as a source of meat protein (Hardouin et al 2003). The use of these animals will alleviate poverty and hunger in these areas as these local animals can be reared using local feed resources and were adapted to this climate (Hardouin et al 2003). Factors affecting animal production therefore play an important role if these animals are to be domesticated. As such some aspects of feeding, feed size, digestive anatomy and nutrition (Henry 1999, Garcia et al 2000, Lall et al 2018a, Dookie et al 2018). The male and female reproductive systems have been reported by Guimares et al (2011), Mollineau et al (2012) and Singh et al (2014). Health and disease have been reported in wild caught agoutis by Lainson et al (2010), Suepaul et al (2016) and Lall et al (2018b) while captive reared agoutis have been reported by Jones and Garcia (2017, 2018b). The weaning age of offspring parameters was reported by Mohammed et al (2018). Next, if these animals are to be reared for production then diseases which affect them must be identified. One such aspect which needs to be recorded is parasites, and according to Jones and Garcia (2018a) parasitic diseases can affect its host clinically and sub-clinically. Clinical diseases can be diagnosed by veterinarians but sub-clinical diseases were not as easily identified, and can have deleterious effects on the animals’ performances. Blood analysis to identify sub-clinical disease has been used by veterinarians to treat and manage domesticated animals (horse, sheep, goat, cow, chicken, pig). Thus blood and serum reference values can be used for the Agouti and needs to be developed. The general objective of this paper therefore, was to provide baseline information on the blood analysis of the male agouti reared in captivity. This would be achieved through: (1) identifying the presence of parasites in the blood and (2) reporting on the complete haematological and serum biochemistry parameters. This is the first known time the complete blood count and serum biochemical values are being reported for the captive-reared Agouti in the Republic of Trinidad and Tobago.

Methodology

Location and climate

Trinidad and Tobago was found to be located 10° 32' 11.1156'' N and 61° 18' 43.0236'' W and at this location a humid tropical climate was experienced. Annual temperatures ranged from 30.0⁰C to 21.0⁰C. Average annual rainfall and relative humidity was recorded as 999.9 mm and 82% respectively. The ten adult male animals used in the study, were conveniently selected from animals housed on concrete floors at the SFC in Longdenville, Central Trinidad. The blood samples were taken from the Agoutis in April 2018 stored in ice (4⁰C) and were analysed 1-2 hours later. Analytical work was conducted at Animedics Pet Hospital located in Chaguanas, also in Central Trinidad.

Animal selection

Convenient samples of animals were taken on the floor pens of the Sugarcane Feeds Centre. The ten (10) male animals chosen were raised in captivity for approximately four (4) years. Animals were given water and feed ad libitium. Their diet consisted of local feed resources which included pumpkin (Cucurbita pepo), mango ( Mangifera indica), cassava (Manihot esculenta) and papaya (Asimina triloba). Animals displayed good body condition score, were not previously treated with anthelmintic, nor had no history of illness. Animals were weighed at the end of the study and a body condition score given before humanely sacrificing them (Ullman-Cullere and Foltz 1999) according to veterinary standard in Trinidad and Tobago.

Sample collection

Animals were physically restrained and blood was collected via the jugular vein when the animal was sacrificed. Blood samples were collected from the jugular vein when the vein was severed and blood collected in an Ethylenediamine Tetraacetic acid (EDTA) tube (Purple top) and another tube containing no anti-coagulant (Red top). Five millilitres (5mls) of blood were collected from each animal and analysed in an Abaxis^® (Abaxis Global Diagnostics). Complete blood analysis was conducted using an Abaxis CBC Analyser (HM5_C), while the Serum Biochemistry was analysed using the Abaxis Chemistry analyser (VS2). One drop of blood of each sample in the EDTA tubes was taken and thin blood smears made. Slides were stained with a Diff-Quik^® and blood cells were observed at the feathered edge under a light microscope for blood parasites (Hendrix and Robinson 2016). Historical work done in South America on agouti blood values were converted to standard form (SI units) for comparison.

The animals’ gastrointestinal content samples were collected and analysed using floatation techniques, where saturated Sodium Chloride solution and were allowed to settle for fifteen (15) minutes before being viewed under a light microscope. The faecal eggs/oocysts were identified and quantified in the Mc Master Slide (Hendrix and Robinson 2016).

Statistical analysis

This descriptive statistical analysis of the blood samples was conducted with the Excel^® 2007 programme.

Results

Blood samples taken (n=10) showed no blood parasites were present in peripheral blood. Hemogram and Serum Biochemistry are shown in Tables 1 & 2.

Faecal samples were collected from animals and tested for gastrointestinal parasites. Those found included: Strongyloides spp., Eimeria spp., and Trichuris spp. Further, animals’ showed a body condition of 3 out of 5. Agoutis in this study had no prior history of disease and were in good body condition.

Animals in the study had an average body condition score of 3 out of 5 and an average live-weight was 2.34 kg (Table 3; taken from Jones and Garcia 2018b).

Discussion

Haematology

Red blood cell (RBC) values in this study were similar to de Aquinos et al (2009) for male Agoutis, but were found to be higher than the 6.51±0.83 x 10¹²/ l that were repoted by Ribiero et al (2008b). Differences in RBC values were attributed to the physiological states of the animals, as in this study, only males were examined, but Ribiero et al (2008b) obtained mean values from different physiological states and genders, (adult male, adult female, juveniles). Notably though, haemoglobin and haematocrit values obtained were within the range of those obtained by Nunes et al (2006) and de Aquino et al (2009), but Ribiero et al. (2008b) reported lower values. Mean corpuscular volume, mean corpuscular haemoglobin concentration and monocytes values also agreed with those of previous studies in Dasyprocta spp. (Nunes et al 2006, Ribiero et al. 2008b, de Aquino et al 2009).

White blood cells, lymphocytes and neutrophils were however not in the range of the previous studies by Nunes et al (2006), Robiero et al. (2008b) and de Aquino et al (2009). In the case of white blood cells, neutrophils and lymphocytes, values for the first two were higher compared to the previous studies, whilst the last were lower. These results suggested that the animals were stressed before their blood was collected. The techniques used in this study will have to be refined as to decrease the level of stress experienced before samples are taken. A stress leukogram was reported to have occurred when apparent leucocytosis, neutrophilia and lymphopenia was found in domesticated animals (Bentink-Smith 1969). Platelets values recorded were less than those obtained by de Aquino (2009) but more than what Robiero et al (2008b) found. However, differences in results obtained, can be due to the collection of samples. If blood that was collected did not properly mix in the tube with anti-coagulant (EDTA), then a higher platelet may have been recorded due to clumping. If samples were stored for an extended period, then platelets will break down and result in decrease amounts being reported. Mean platelet volume (MPV), plateletocretin, platelet distribution width (PDW), red cell distribution width (RCDW) were reported for the first time for captive-reared Agouti, and are now baseline. The study where Cazabon et al (2000) examined blood profile of rabbits reared intensively in Trinidad, was the only similar study done locally and the results obtained were not similar to those of this study. The present agoutis had higher values on haemoglobin, haematocrit, WBCs and neutrophils of 12.3 g/dl, 38.6% and 39.2% respectively. Differences noted were attributed to species studied. According to Kronfield and Medway (1969), differences in blood values were reported to have occurred with variable ages, sexes, physiological states and species.

Serum biochemistry

There were differences in several biochemical profiles between this study and the past studies. Ribiero et al (2008b) recorded alkaline phosphatase and alanine transferase values that were lower than those found in this study at 119.54±79.35 U/l and 28±15.53 U/l respectively. Alkaline phosphatase and alanine transferase levels are biochemical identifiers which are used to assess liver function. Variation in the diets and environmental conditions between the two studies would account for the differences in liver enzyme function observed (Kronfield and Medway 1969). Also, Nunes et al (2006) observed calcium (10.4±1.68 mg/dl) and phosphorus (7.48±1.20 mg/dl) values that were lower than those found for this study. These values too, can vary based on differences in the diet; as different soil conditions can produce local feedstuff that will have varying constituents. Next, Glucose values recorded for agoutis in Colombia were 249.9±47.1 mg/dl (Nunes et al 2006). Lower values obtained in this study, but Nunes et al (2006) used a sedative before collecting blood, while this used study physical restraint. According to Kronfield and Medway (1969) high glucose values occurred both in excited animals and after meal. Thus the high glucose level noted by Nunes et al (2006) may be due to hyperglycaemia post meal consumption. This study, based literature searched is the first to investigate serum biochemical parameters such as amylase, sodium, potassium, total bilirubin and blood urea nitrogen for captive-reared Agouti, and now constitute baseline information for this group.

Blood parasites

Blood parasites were identified in wild Agoutis in Brazil and they are: Leishmania mexicana guanensis (Lianson et al 1981), in the rainforest in French Guiana; Babesia spp., Filaria and Trypanostonatidae (de Thoisy et al 2000) and Trypansoma spp. (found in wild Dasyprocta fuliginosa) in Colombia (Ayala et al 1973). The present study identified no blood parasites however. This may be explained by the fact that agoutis living in the wild were exposed to the vectors such as the sand-fly (Phlebotamus papatasi) and the reduviid bug, (Triatoma infestans) which transfer the blood parasites. In captivity no such exposure occurred. Additionally, identification of gastrointestinal parasites (Jones and Garica 2018b) in the current study had no effect on the animals’ body conditions and also appeared not to have affected the blood values observed.

Eosinophils generally identify the presence of sub-clinical infections of parasitic diseases. In this study however, no eosinophils were observed (0.00±0.00), therefore the parasitic load present did not affect the animals sub-clinically. Therefore the relationship these organisms termed parasites in the digestive tract of the Agouti have with it needs to be re-evaluated. It must be noted that if these “parasitic” organisms have no detrimental effects on these animals clinically or sub-clinically then the relationship between these organisms and their host was not parasitic but is in fact mutualistic or commensalistic.

Conclusions

• No blood parasites were found in captive-reared agoutis at the Sugarcane Feeds Centre.
  
  
• Most of the blood and serum biochemistry parameters were similar to other sources even though some animals had parasitic gastrointestinal infestation.

Conflicts of Interest

There was no conflict of interest amongst authors

Authors’ contributions

KRJ and KRL collected blood samples and analysed the results. KRJ formally wrote the initial draft of the manuscript. KRJ, KRL. and GWG. made revisions to the initial draft document. GWG supervised the entire project.

Acknowledgements

Special thanks go to Mr. Rajesh Bhajan at the SFC for providing the animals. Without your animals and help this research would not have been possible. Thanks must also be given the Dr. Sawh at the Animedics Pet Hospital for providing facilities for analysis of the blood samples. This project was funded by the Campus Research and Publication unit at the University of the West Indies, St Augustine Campus.

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Received 18 October 2018; Accepted 29 November 2018; Published 1 January 2019

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