The composition of milk from free‐living common marmosets (Callithrix jacchus) in Brazil

Abstract

Common marmosets, one of the smallest anthropoid primates, have a relatively high reproductive rate, capable of producing twins or triplets twice per year. Growth and development of infants is relatively rapid, and lactation is relatively short at less than 3 months. Although mean values for the proximate composition (dry matter, protein, fat and sugar) of captive common marmoset milks fall within anthropoid norms, composition is highly variable among individual samples, with concentrations of milk fat ranging from below 1 to over 10%. To examine the extent to which this variation might be a consequence of captive conditions, we collected milk samples from wild common marmosets freely living on a farm in the state of Rio de Janeiro, Brazil. The proximate composition of the milk samples was assayed using identical techniques as used for the captive marmoset milks. The composition of the milk of wild common marmosets was also variable, but tended to be lower in dry matter, fat, protein and gross energy, and higher in sugar than milks from captive animals. Interestingly, the percentage of estimated gross energy from the protein fraction of the milks was relatively constant in both wild and captive marmosets and did not differ between wild and captive animals: lkcal of common marmoset milk contains on average (+ SEM) 0.035 + .001 g of protein regardless of the gross energy content of the milk or whether the milk was from a wild or captive animal. In contrast, in 1 kcal of low-energy milks, the amount of sugar was significantly higher and the amount of fat significantly lower than in 1 kcal of high-energy milks. Thus, common marmoset milk exhibits axes of variability (especially fat concentration) as well as a significant stability in the relative amount of protein. Am. J. Primatol. 70:78-83, 2008.

Primate milk: Proximate mechanisms and ultimate perspectives

“…37 Moreover, twins born to small mothers were smaller and had slower growth rates than did singletons or twins born to larger mothers. 37 Milk samples from wild living C. jacchus 19 were similar to those from captive living C. jacchus in percent energy from protein, 18 but were lower in fat, total protein, and gross energy. The consistency in percent energy from protein, regardless of diet and environment, may be an adaptation in C. jacchus arising from requirements for infant growth and development.…”

“…14 Generally, protein concentration and energy from protein are high in species exhibiting accelerated infant growth. 3,18,19 Dilute milks are associated with species living in the opposite conditions of those described thus far. In arid environments, milk not only provides energy, but also maintains infant hydration; high water turnover favors dilute milks in camelids and equids.…”

“…The consistency in percent energy from protein, regardless of diet and environment, may be an adaptation in C. jacchus arising from requirements for infant growth and development. 19 Milks from both populations were variable in fat and total gross energy, but there was a smaller range of variation in fat among wild living C. jacchus (1.4%-3.2%) compared to their captive conspecifics (2.1%-5.3%). 19 Recently, research on captive M. mulatta has shown that maternal health and life history are associated with milk synthesis.…”

“…19 Milks from both populations were variable in fat and total gross energy, but there was a smaller range of variation in fat among wild living C. jacchus (1.4%-3.2%) compared to their captive conspecifics (2.1%-5.3%). 19 Recently, research on captive M. mulatta has shown that maternal health and life history are associated with milk synthesis. Mothers with intestinal parasites produced milk with significantly lower fat concentration than did mothers without parasites.…”

“…34 Captivity may similarly influence milk synthesis. 19 Wild common marmosets and toque macaques (C. jacchus and Macaca sinica) show less variation in milk composition than do captive primates. Also, mean fat concentration is lower in wild primates (Table 1).…”