Milk production of the dam limits the growth rate of Sundevall's jird (Meriones crassus) pups

Abstract

a b s t r a c tWe determined metabolizable energy intake (MEI), body energy change and milk production in primiparous, lactating Sundevall's jirds (Meriones crassus) when nursing litters of two to six pups. We hypothesized that milk production was a constraint and that pups in small litters would have a faster growth rate than pups in large litters. We also hypothesized that females with small litters would offset the costs predominantly with metabolizable energy intake while females with large litters would be forced to mobilize more body energy. There was a negative relationship between growth rate of a pup and litter size which would imply that milk production was the limiting factor in pup growth, which supports our first hypothesis. Although there was an increase in maternal milk production with an increase in litter size, there was a decrease in milk intake per pup with litter size. There was a significant correlation between loss in body energy and litter size, that is, an increase in litter size was associated with more maternal body energy loss, which supports our second hypothesis. MEI in lactating females was on the average 35% above that of non-reproducing females and, together with litter size explained 74% of the variance in the growth rate of a pup. Each of these independent variables contributed about equally to the variance.

Dietary protein influences the life‐history characteristics across generations in the African striped mouse Rhabdomys

“…Reduced body mass at birth, due to slow fetal growth, has been demonstrated for Wistar rat pups born to protein‐restricted mothers, and is assumed to be due to a limited supply of nutrients to the fetuses caused by an inability of the smooth muscle of the uterine artery to dilate, creating vascular resistance and reduced uterine artery blood flow (Molina‐Font, ; Koumentaki et al, ) as well as diminished nutrients to the fetuses (Ahokas et al, ; Itoh et al, ; Koumentaki et al, ). Comparatively small litter sizes of the LP treatment may also be a consequence of energetic demands that a larger litter places on the mother (Sadlier, ; König et al, ; Kenagy et al, ; Degen et al, ), and females bred on the LP diet might not have been able to acquire enough protein to invest in larger numbers of fetuses.…”

Impact of thermal convection on air circulation in a mammalian burrow under arid conditions

“…(6). This production rate is an order of magnitude lower than the average venting rate by TCV that was measured experimentally, which was designed to represent the opening of a burrow of a M. crassus that weighs around 0.1 kg (Degen et al, 2011) and its calculated _ V CO2 ¼ 2 mL/min. Therefore, during the night, atmospheric conditions will prevail inside the opening of a burrow of M. crassus due to the fast venting rate of TCV.…”

Host reproductive status and reproductive performance of a parasite: offspring quality and trade-offs in a flea parasitic on a rodent

“…Under these conditions, oviposition starts on the second day or later (Khokhlova et al 2012). Since M. crassus females have an oestrous cycle of 4–4·5 days and a pregnancy of 18–22 days, and pups start eating solid food at 17 days (Krasnov et al 1996; Khokhlova et al 2000; Kam et al 2003; Degen et al 2011), pregnant and lactating females in our experiments were thus parasitized in the middle of pregnancy or at peak lactation, respectively.…”

“…Under these conditions, oviposition starts on the second day or later (Khokhlova et al 2012). Since M. crassus females have an oestrous cycle of 4-4•5 days and a pregnancy of 18-22 days, and pups start eating solid food at 17 days (Krasnov et al 1996;Khokhlova et al 2000;Kam et al 2003;Degen et al 2011), pregnant and lactating females in our experiments were thus parasitized in the middle of pregnancy or at peak lactation, respectively. Seventy-two hours after releasing fleas in a rodent cage, we collected fleas from the rodent's body (over a white plastic pan using a toothbrush until no flea was recovered) and bedding substrate, placed fleas recovered from the same rodent individual in a Petri dish and transferred them to an incubator (FOC225E, Velp Scientifica srl, Milano, Italy) at 25°C air temperature and 90% relative humidity (RH) for 24 h. The next day (that is, day 4 of the experiment), we placed each rodent in a wire mesh tube (5 mm by 5 mm mesh; 15 cm length and 5 cm diameter) to prevent self-grooming.…”