Milk Composition of Asian Elephants (Elephas maximus) in a Natural Environment in Myanmar during Late Lactation

Physiological changes in captive elephants in Northern Thailand as a result of the COVID-19 tourism ban - muscle, liver, metabolic function, and body condition

The international travel ban initiated in March 2020 due to the COVID-19 pandemic greatly affected how captive elephants were managed in Thailand. A lack of tourists and associated income meant elephants were chained longer with reduced food provisions, had fewer mahouts, and limited exercise like riding, which likely affected health and welfare. Fifty-eight elephants from six tourist camps were assigned a body condition score (BCS) and blood samples were collected monthly for 2 years during the travel ban to measure: (1) muscle enzymes [creatine kinase (CK), aspartate aminotransferase (AST)]; (2) liver enzymes [aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT)]; (3) lipids [total cholesterol (TC), triglycerides (TG), low (LDL) and high (HDL) density lipoproteins]; and metabolic function [glucose, insulin, fructosamine]. Serum CK concentrations were lower at the end of the study, possibly due to no tourist activities like riding. Changes in liver function included increased AST and ALP, also possibly due to physical inactivity. Feeding less bananas and sugar cane was associated with fewer elephants in the obese category and lower TG concentrations. However, increases in glucose, insulin and fructosamine were observed as local people returned to feed elephants after lifting travel restrictions. In sum, changes in several health biomarkers were observed in association with restricted activities and food resources. Camps need better plans to meet the health and welfare needs of elephants during any future disruptions to the tourism industry, although reduced feeding of sweet treats appeared to have positive effects on body condition and metabolic function.

The Gut Microbiota of Young Asian Elephants with Different Milk-Containing Diets

Evaluating the association between milk-containing diets and the microbiomes of young Asian elephants could assist establishing optimal breast milk supplementation to improve offspring survival rates. The microbiomes of young Asian elephants on different milk-containing diets (elephant milk only, elephant milk-plant mixed feed, and goat milk-plant mixed feed) were investigated using high-throughput sequencing of 16S rRNA genes and phylogenetic analysis. Microbial diversity was lower in the elephant milk-only diet group, with a high abundance of Proteobacteria compared to the mixed-feed diet groups. Firmicutes and Bacteroidetes were dominant in all groups. Spirochaetae, Lachnospiraceae, and Rikenellaceae were abundant in the elephant milk-plant mixed-feed diet group, and Prevotellaceae was abundant in the goat milk-plant mixed-feed diet group. Membrane transport and cell motility metabolic pathways were significantly enriched in the elephant milk-plant mixed-feed diet group, whereas amino acid metabolism and signal transduction pathways were significantly enriched in the goat milk-plant mixed-feed diet group. The intestinal microbial community composition and associated functions varied significantly between diets. The results suggest that goat milk is not suitable for young elephants. Furthermore, we provide new research methods and directions regarding milk source evaluation to improve elephant survival, wellbeing, and conservation.

African Elephant Milk Short Saccharide and Metabolite Composition and Their Changes over Lactation

Elephant milk composition is unique, as are its changes over lactation. Presented here is the milk non-dedicated metabolite composition of three African elephants. Their lactation times are overlapping and span day one to thirty months. Metabolites were identified and quantified by ¹H nuclear magnetic resonance spectroscopy. Lactose and short oligosaccharides are a large component of the metabolites, with lacto-N-difucohexaose I as the major oligosaccharide. These were followed by metabolites of lipids, amino acids, and the citric acid cycle. The content of lactose, lacto-N-difucohexaose I, 2'-fucosyllactose, and some unidentified oligosaccharides decrease over lactation, while that of difucosyllactose and other unidentified ones increase. The high content of glutamate, as a glucogenic amino acid, supported the uprated synthesis of saccharides by the milk gland cells. The content of succinate and choline increase over lactation, indicating higher energy expenditure and phospholipid synthesis during later lactation.

Macronutrient composition of milk from two captive African elephant (Loxodonta africana) cows

We assayed 31 milk samples collected from two African elephant cows housed at the Indianapolis Zoo across lactation (birth to calf age 973 days) for macronutrient composition (water, fat, protein, sugar, gross energy [GE], ash, calcium, and phosphorus). All assays were performed at the Smithsonian National Zoological Park Nutrition Laboratory, Washington, DC (SNZP) using standard methods developed at SNZP. Milk constituents are expressed on a weight-per-weight basis (%) and as a proportion each constituent contributes to milk energy. Calf weights were recorded, and growth rate calculated. The macronutrient composition of the African elephant milk samples was compared to previously published results for Asian elephants using analysis of covariance. African elephant milk is similar to Asian elephant milk, being moderately high in fat and energy and low in sugar. The mean values across lactation (excluding colostrum; n = 28) are 5.6 ± 0.3% crude protein, 3.1 ± 0.3% sugar, 13.0 ± 1.0% fat, and GE of 1.63 ± 0.10 kcal/g. Milk composition did not differ between cows. Milk composition significantly changed over lactation; fat and protein increased, and sugar decreased with calf age, comparable to previously reported data for African and Asian elephant milk. The proportion of milk energy from fat increased and that from sugar decreased over lactation, but the energy from protein was relatively constant. Protein contributed a higher proportion of energy to African elephant milk compared to Asian elephant milk (20.6% vs. 17.0%, p = .001). Despite this, calf growth rate was similar between the species, with the calves in this study gaining about 0.8 kg/day for the first 6 months.

Seasonal variation of health in Asian elephants

Long-lived species are often predicted to be buffered against seasonal variation: longevity means low annual mortality and reproductive rates and annual variability in climate may therefore have a smaller impact on population growth rates of long-lived species in comparison to short-lived ones. However, little is known of the physiological mechanisms underlying such patterns in long-lived species. In this study, we investigated seasonal variation in the health of Asian elephants living in a seasonal monsoon climate. We used two complementary methods: (i) global and (ii) trait-by-trait analyses of seasonal effects on 23 health parameters of 225 individually marked elephants with known age and reproductive and health history, with repeated measures per individual over a 26-month period. The global analysis highlighted the biggest differences in health between the hot and monsoon seasons. Our trait-specific analyses identified the physiological functions underlying such health variation in different ecological settings, including haematological, immunological, muscular, kidney and liver functions, as well as protein balance and electrolytes. Overall, the results suggest that even long-lived, large mammals may experience physiological changes in response to seasonal variation that in extreme circumstances can pose a significant health risk.