Major constituents, leptin, and non-protein nitrogen compounds in mares' colostrum and milk

Abstract

-Five Haflinger mares were hand-milked at 0 h (pre-suckle) and 6 h (postsuckle), 12, 24, 48, 72 and 96 h after parturition. Total solids, protein, fat, lactose, calculated gross energy content, leptin and non-protein nitrogen components (urea, a-amino nitrogen, creatinine and allantoin) were determined. The levels of the major constituents differed significantly in pre-suckle colostrum from subsequent samples. Leptin levels were the highest in whole (9 ng . mL -1 of immunoreactive human equivalent HE ± 0.48 ng . mL -1 , SEM) and skimmed (7.8 ng HE . mL -1 ± 0.52 ng . mL -1 , SEM) pre-suckle colostrum, declined sharply at 6 hours postpartum, and more slowly subsequently. Mean urea concentration was constant at around 5.0 mM, while a-amino N increased over the observation period and creatinine and allantoin decreased. These findings provide a further indication that mares' milk can be regarded as a functional food. mares' milk / colostrum / major constituents / leptin / non-protein nitrogenRésumé -Principaux constituants, leptine et métabolites d'azote non protéique dans le colostrum et le lait de jument. Cinq juments Haflinger ont été traitées à la main aux temps 0 (avant tétée) et 6 (après tétée), 12, 24, 48, 72 et 96 heures après le poulinage. Les paramètres évalués sur ces échantillons ont été les principaux constituants de la sécrétion mammaire (matière sèche, protéines, lipides, lactose), le contenu énergétique brut et la leptine ; en plus, on a considéré les teneurs en urée, a-aminoacides, créatinine et allantoïne. Une différence significative a été observée entre les valeurs enregistrées dans le colostrum prélevé avant la tétée et dans les autres échantillons. De même, des variations dynamiques concernant la leptine immunoréactive ont été relevées au cours de l'essai : les valeurs étaient les plus fortes dans le lait entier (9 ng . mL -1 équivalent de leptine humaine HE ± 0,48 ng . mL -1 , SEM) et dans le colostrum écrémé (7,8 ng HE . mL -1 ± 0,52 ng . mL -1 , SEM) prélevés avant la tétée. La concentration en urée était en moyenne de 5,0 mM et la concentration en azote des a-aminoacides dénote des bilans différents par rapport à celui mis en évidence pour la créatinine et pour l'allantoïne. Ces résultats contribuent à faire considérer le lait de jument comme un aliment fonctionnel.lait de jument / colostrum / constituants du lait / leptine / non-protein nitrogen Reprod. Nutr. Dev. 42 (2002) 65-72 65

Equid milk for human consumption

“…Among the NPN components of equid milk, the average urea content (20e35 mg 100 g À1 ) is consistent with data from cow milk, but slightly lower than those from human milk (Darragh & Lonnerdal, 2011;Dell'Orto et al, 1994;Fantuz et al, 2009b;Martuzzi et al, 2004;O'Connell & Fox, 2011) and it represents approximately 40% of the NPN fraction in horse and donkey milk (Fantuz et al, 2009b;Salimei, Varisco, & Rosi, 2002). This could be related to the different metabolic abilities among mammalians in recycling urea.…”

“…Furthermore, in horse and donkey mammary secretion, defatted or not, growth factors and hormones have also been determined through radioimmunoassay or ELISA methods that use human peptides as standard and specific antibodies, properly validated for the equid species. In detail, horse and donkey mammary secretions contain human-like leptin at levels (3.35e5.32 ng mL À1 milk; Salimei et al, 2002Salimei et al, , 2005bSalimei, Rosi, Maglieri, Magistrelli, & Fantuz, 2007) close to human milk (Bonnet et al, 2002). The bioactive peptides insulinlike growth factor 1 (IGF-1, 9.81e13.50 ng mL À1 milk), ghrelin (4.26e4.63 pg mL À1 milk; Magistrelli, Rosi, Amicone, Maglieri, & Salimei, 2008) and triiodothyronine (T3, 4.0 ng mL À1 milk; Todini, Malfatti, Salimei, & Fantuz, 2010) were also found in frozen donkey milk.…”

Enhanced or Reduced Fetal Growth Induced by Embryo Transfer into Smaller or Larger Breeds Alters Post-Natal Growth and Metabolism in Pre-Weaning Horses

“…Similarly, increased milk production in draft mares could account for the growth advantage in P-D foals, since milk yields are known to be breed specific [61] and to be increased with the mare's size [61]. Hormones and growth factors such as T 3 [62], leptin [63], IGF-1 and insulin [64] and thyroid stimulating hormone (TSH) [49] are also supplied through the mare's colostrum. In Quarter horses, milk leptin, IGF-1 and TSH concentrations were at their maximum the day of parturition and reached minimum at 2 months postpartum (leptin and TSH) or became undetectable by 12 days postpartum (IGF-1) [49].…”

Fat and cholesterol content and fatty acid composition of mares' colostrums and milk during five lactation months

“…A study by Salimei et al (2002) on mare's mammary secretion (multiparous Haflinger) showed a significant increase of the fat content in the first 6 h from foaling reaching 2.49%. After 12 h from foaling the fat Fatty acids: SFA (saturated fatty acids) -sum of SCFA + MCSFA + LCSFA.…”

“…The colostral period of mares was found to be much shorter than that of cows and the colostrum showed significant differences from normal milk only Available online at www.sciencedirect.com Livestock Science 113 (2008) 285 -290 www.elsevier.com/locate/livsci on the first day after foaling. Salimei et al (2002) showed a significant increase of the fat content in the first 6 h from foaling. The dry matter content of mares' milk decreased drastically from colostrum to normal milk, due, primarily, to a decrease in protein content.…”