Effects of altering diet carbohydrate profile and physical form on zoo-housed giraffe Giraffa camelopardalis reticulata

Authors: KEARNEY, CELESTE - University Of Florida; BALL, RAY - Busch Gardens - Tampa Bay; Hall, Mary Beth

Submitted to: Journal of Animal Physiology and Animal Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/2024
Publication Date: 4/9/2024
Citation: Kearney, C.C., Ball, R., Hall, M. 2024. Effects of altering diet carbohydrate profile and physical form on zoo-housed giraffe Giraffa camelopardalis reticulata. Journal of Animal Physiology and Animal Nutrition. https://doi.org/10.1111/jpn.13957.
DOI: https://doi.org/10.1111/jpn.13957

Interpretive Summary: Knowing what to feed a captive wild animal can be a challenge. Unlike domestic livestock, there is little information available regarding their requirements and what constitutes a diet that will keep them healthy. In this study, captive giraffe were offered a commercial blended supplement feed (CTRL) or an experimental supplement (EXP) that was coarse in texture, and contained more sugars and soluble fiber, and less starch than the control supplement. Alfalfa hay, salt, and water were available free choice to the animals. The giraffe offered EXP spent more time eating. Those animals also had blood glucose values that were lower than seen with CTRL and more in line with values seen with some domestic ruminants. The study offered proof that modifying the carbohydrate profile and physical form of the diets could influence behavior and blood values in captive giraffe. It offers promise for exploring other diet modifications to ensure the captive animals' well-being.

Technical Abstract: Unlike wild giraffe that primarily consume low starch browse, captive giraffe have shown preference for consuming supplement feeds over forage. This could increase their risk of digestive disorders such as ruminal acidosis that have been noted in livestock consuming diets high in concentrate feeds and starch. The objective of this study with captive giraffe was to evaluate effects of modifying a supplement’s nonfiber carbohydrate profile and physical form on nutritional, behavioral, and blood measures. Six non-lactating, adult, female reticulated giraffe were used in a two pen modified reversal study using two dietary treatments in seven 21-day periods with data collected days 15 through 21. Dietary treatments included a combination of commercially available feeds comprising the control supplement (GF) and an unpelleted experimental feed (EF). Respectively, GF and EF contained on a dry matter basis 17.0 and 17.4% crude protein, 14.2 and 1.46% starch, 14.9 and 21.3% ethanol-soluble carbohydrates, 22.9 and 26.0% acid detergent fiber (ADF), and 9.50 and 14.9% neutral detergent-soluble fiber (NDSF), and modulus of fineness values of 3.62 and 4.82. Supplements, alfalfa hay, salt, and water were available ad libitum. Significance was declared at p < 0.10. Intake of hay, supplement, and total feed did not differ by diet (p > 0.28), though intakes of starch (0.93 and 0.12 kg; p = 0.05), ADF (1.83 and 2.23 kg; p = 0.04), and NDSF (0.85 and 1.19 kg; p = 0.07) differed between GF and EF, respectively. Giraffe behavior values (min/48 h) were greater with EF for standing (p = 0.07), supplement consumption (p = 0.06), total eating (p = 0.04), and eating + rumination (p = 0.08); time spent engaged in oral stereotypes did not differ by diet, but was numerically greater with GF than EF (433 and 318 min/48 h; p = 0.22). Glucose was the only blood value detected as different with GF greater than EF (99.0 and 82.3 mg/dL; p = 0.03). The lower blood glucose value with EF is more similar to ranges reported for other ruminants. No differences were detected for changes in body weight or body condition score in the 21-d periods (p > 0.32). Modification of supplement carbohydrate profile and physical form can influence behavior and blood glucose values of captive giraffe.