Plus-Hex CLINICAL
Table 1. PICo and search terms. Adapted from RCVS Knowledge [ 36 ].
PICo Search terms Synonyms and related keywords
Patient or population
Guinea pig Guinea pigs Cavia porcellus Cavies Rodent Rodentia Rodents
Intervention Diet Nutrition, nutritional Dietary requirements Deficiency, deficiencies, deficient Feeding, food, feed
Diets Accommodation Housing, home Enclosure Living
Environment Context Population as pets Pets, companion animals Domestic, domesticated
Findings
The findings from the six studies are compiled and summarised in Appendix 2. There are a number of owner-reported surveys [ 49 – 52 ] investigating owners ' knowledge of diet, husbandry and housing of guinea pigs. Harrup and Rooney [ 49 ] concluded that UK guinea pigs would benefit from increased veterinary visits and owner education, which Cameron et al. [ 52 ] support regarding husbandry in New Zealand.
Norman and Wills [ 50 ] found owners to be knowledgeable, and found no link between diet and dental disease, but do not state the country in which the investigation took place, so results cannot be generalised. Witkowska et al. [ 51 ] found discrepancies between diets in the UK and Poland, and all authors agreed that evidence-based information is difficult for owners to navigate.
Schumann et al. [ 53 ] and Trejo-Sanchez et al. [ 54 ], investigating laboratory C. aperea and C. porcellus used in agriculture, respectively, were included in the literature review as there is limited research on pet guinea pigs. Schumann et al. [ 53 ], in Germany, found that housing affected weight and blood cortisol levels. Trejo- Sanchez et al. [ 54 ] found that rabbit food fortified with vitamin C was suitable to feed guinea pigs.
Although the findings can be generalised only to their study ' s location( s) and sample characteristics, a varied view of guinea pigs living around the world is revealed [ 38 ].
Limitations
Risk of lying or exaggeration exists with all questionnaires and, consequently, it is debatable whether meaningful conclusions can be drawn at all [ 55 ]. However, non-participation may be more likely than dishonesty, so the data are still useful [ 56 ]. Questionnaires are a valid method for describing‘ what is’ quantitatively, and did mostly address the researchers’ aims [ 48 ]. Guinea pigs cannot describe their own phenomenology in human language so, to have a chance of being understood, obtaining insight from owners is reasonable [ 57 ]. This, however, relies on subjective interpretation, where animal behaviour and questions can be misunderstood.
Blood cortisol is debatable as a valid measurement of stress due to its adaptive functions, and handling methods can cause significant stress [ 58 ]. For example, the guinea pigs may have anticipated stressful events from their companions ' vocalisations [ 58 ]. Schumann et al. [ 53 ] do, however, recognise the influence of human presence and other external influences in their experiments, and weights were impacted by housing condition regardless of social dynamic. Retrospective studies are also cost- and time-effective, and can help inform prospective studies [ 59 ].
Trejo-Sanchez et al. [ 54 ] concluded, arguably rather hastily, that rabbit food is suitable for guinea pigs. Their study contained internal and external methodology issues, such as stating that food was given ad libitum twice daily, which can be considered as two different things, not stating how morphometric values were measured, and not stating why ivermectin was administered before and after the experiment and whether it was due to any health conditions or prophylactically, all of which affect the trustworthiness of the results [ 60 ]. Furthermore, Trejo-Sanchez et al. [ 54 ] stated that they measured various anatomical parameters of the guinea pigs, such as body size and bone lengths, but it is unknown whether morphology was analysed when the guinea pigs were alive or postmortem. This makes ethical issues, including welfare and euthanasia methods and the psychological burden on the researchers, difficult to assess [ 61 ].
Despite issues with validity and reliability, the findings provide an overview of guinea pig care quality and can inform future studies of higher rigour [ 62 ]. Achieving absolute rigour in research is extremely difficult; highly rigorous research means only that it was executed as well as possible, not that the findings are indisputable [ 63 ].
Volume 40( 5) • October 2025
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