Effect of Dietary Energy Level during Late Gestation on Mineral Contents in Colostrum, Milk, and Plasma of Lactating Jennies.

This study investigated the effects of dietary energy levels during late gestation on mineral content in the plasma, colostrum, and milk of jennies postpartum. Twenty-four pregnant multiparous DeZhou jennies, aged 6.0 ± 0.1 years, with a body weight of 292 ± 33 kg, an average parity number of 2.7 ± 0.1, and similar expected dates of confinement (74 ± 4 days), were randomly allocated to three groups and fed three diets: high energy (12.54 MJ/kg, HE), medium energy (12.03 MJ/kg, ME), and low energy (11.39 MJ/kg, LE). Blood samples were collected from the jugular vein of each jenny at time points of 0 h, 24 h, 48 h, 5 d, 7 d, and 14 d after parturition. Additionally, milk samples were collected through manual milking, and an analysis of the mineral content was conducted. The results showed that compared with HE, both ME and LE significantly increased the levels of calcium (Ca), phosphorus (P), zinc (Zn), selenium (Se), molybdenum (Mo), and cobalt (Co) in the plasma and Ca, P, magnesium (Mg), copper (Cu), manganese (Mn), Zn, selenium (Se), molybdenum (Mo), and Co in the milk of jennies postpartum (p < 0.05); ME also increased the levels of potassium (K), iron (Fe), and Mn in plasma and K and Fe in milk (p < 0.05). The levels of Ca, K, Mg, P, Fe, Cu, Mn, Co, Se, Zn, and Mo in plasma and milk gradually decreased with increasing postpartum time. Their contents were the highest at 0 h postpartum, rapidly decreased after 24 h postpartum, and declined to the lowest on day 14 postpartum. The interaction between dietary energy level and postpartum time showed that although the concentrations of the minerals Ca, P, K, Mg, Fe, Cu, Mn, Zn, Co, Se, and Mo decreased in jennies' plasma and milk in the treatment groups with different energy levels as postpartum time increased, the pattern of change was also influenced by dietary energy level. The influence of dietary energy level in late gestation on the mineral content of milk and plasma during the postpartum colostrum phase was higher than that during the milk phase. In conclusion, this study demonstrated that, under the current experimental conditions, the mineral content of the colostrum, milk, and plasma of jennies after parturition was dependent on the dietary energy level during late gestation.

Effects of Dietary Selenium Yeast Supplementation on Lactation Performance, Antioxidant Status, and Immune Responses in Lactating Donkeys.

Donkey milk is a traditional medicinal food with various biological activities. However, its production is very low, and lactating donkeys often experience oxidative stress, leading to a further decline in milk yield. In this study, we supplemented the diets of lactating donkeys with yeast selenium (SY) to investigate its effects on lactation performance, antioxidant status, and immune responses, and we expected to determine the optimum additive level of SY in the diet. For this study, 28 healthy lactating Dezhou donkeys with days in milk (DIM, 39.93 ± 7.02 d), estimated milk yield (EMY, 3.60 ± 0.84 kg/d), and parity (2.82 ± 0.48) were selected and randomly divided into 4 groups of 7 donkeys in each: Group SY-0 (control), Group SY-0.15, Group SY-0.3, and Group SY-0.5, with selenium supplementation of 0, 0.15, 0.3, and 0.5 mg of Se/kg DM (in form of SY) to the basal diet, respectively. The results showed a dose-dependent increase in milk yield, milk component yield, milk protein production efficiency, milk production efficiency, the activities of glutathione peroxidases (GSH-Px), catalase (CAT), and total antioxidant capacity (T-AOC), as well as the content of serum interleukin-10 (IL-10), white blood cells (WBC), lymphocytes (LYM), red blood cells (RBC), hematocrit, plasma selenium, and milk selenium. Conversely, it presented a dose-dependent decrease in the activity of nitric oxide synthase (iNOS) and the contents of malondialdehyde (MDA), reactive oxygen species (ROS), nitric oxide (NO), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and interferon-γ (IFN-γ). In conclusion, the results confirmed that dietary supplementation with SY can improve lactation performance, antioxidant status, and immune responses in lactating donkeys, and the recommended dose of SY was 0.3 mg/kg.

Effect of Varying Dietary Crude Protein Level on Milk Production, Nutrient Digestibility, and Serum Metabolites by Lactating Donkeys.

Donkey milk is considered as a functional food due to its high levels of whey protein, and can be used in newborn nutrition, due to the nutritional similarities with human milk and its hypoallergenic property. However, donkey milk yield is very low and little is known about improving donkey milk yield by nutrition manipulation. The effect of dietary crude protein (CP) levels on milk production, nutrient digestibility, and serum metabolites was investigated in the current study. Twenty-four lactating donkeys were randomly assigned to one of the following three CP content diets: 15.3% (HP), 14.2% (MP), and 13.1% (LP) of dry matter, respectively. The experiment lasted for 10 weeks, with the first two weeks being used for adaptation. The results showed that milk yield and yields of protein, lactose, solid-not-fat, total solid, and contents of protein, total solid and milk urea nitrogen in the HP and MP groups were higher than the LP group. No significant changes were observed in dry-matter intake, contents of milk fat, lactose or solid-not-fat. The feed conversion ratio, milk protein synthesis efficiency, and the digestibility of dry matter, crude protein, ether extract, acid detergent fiber, neutral detergent fiber, calcium and phosphorous in the HP and MP groups were greater than the LP group. Serum total protein, albumin and urea nitrogen concentrations decreased, while concentrations of non-esterified fatty acids and ß-hydroxybutyrate increased in the LP group compared with the HP and MP groups. In conclusion, the diet containing 14.2% CP supplied an adequate amount of protein for improving milk production in lactating donkeys, but milk production was not further increased by feeding the donkeys more than 14.2% CP.

Effects of Yucca schidigera extract on growth performance and antioxidative function of small intestine in broilers.

Dietary Yucca schidigera extract (YSE) could enhance immune function in broilers, which was attributed primarily to its saponin components. However, YSE also contains phenolic compounds which possess antioxidant ability. This study tested the effects of YSE on growth performance of broilers, its antioxidative enzyme activities and corresponding gene expressions in the small intestine. A total of 128 15-day-old broilers were randomly assigned to 4 treatments: corn-soya bean meal as the basal control diet or the basal diet containing either 100, 200 or 300 mg/kg of YSE. Each treatment consisted of four replicate pens with eight broilers per pen. The experiment lasted 28 days which was divided into a grower period (day: 15-28) and a finisher period (day: 29-42). On day 28 and day 42 body weight (BW), feed intake (FI) and feed conversion rate (FCR) were recorded. Duodenum, jejunum and ileum were collected to analyse superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities, malondialdehyde (MDA) concentrations, total antioxidant capacity (T-AOC) and gene expressions of SOD, CAT, GPx. The results showed that during the grower period a diet including 100 mg/kg YSE improved CAT capacity in the ileum, tended to increase activities of GPx in the duodenum, and further showed enhancing tendencies in SOD and GPx abilities in ileum. Gene expressions of CAT, SOD and GPx in the ileum tended to upregulate at 100 mg/kg YSE level. In the finisher period and over the whole period, all YSE groups had a reduced FI compared to the control group without compromising BW; 100 and 200 mg/kg YSE significantly improved FCR. In conclusion, the improved growth performance of broilers during the finisher period may be due to enhanced antioxidative ability in the grower period with YSE supplementation. This study provided evidence of using YSE as an additive to enhance growth in broilers.

Effects of dietary supplementation of Artemisia argyi aqueous extract on antioxidant indexes of small intestine in broilers.

The present study was conducted to investigate the effect of Artemisia argyi aqueous extract (AAE) on antioxidant indexes in the small intestine. A total of 192 Arbor Acre broiler chickens (one-day-old) were randomly divided into 4 treatments with 6 replicates of 8 chickens. These 4 diets were formulated by adding 0, 500, 1,000 and 2,000 mg/kg AAE to the basal diet. The results showed as follows: 1) compared with the control, the total antioxidant capacity (T-AOC) in ileum for the 2,000 mg/kg treatment group was significantly increased at 21 days of age (P < 0.05); the T-AOC levels in jejunum and ileum were significantly increased in broilers supplemented with 500 mg/kg AAE at 42 days of age (P < 0.05), and the T-AOC levels in jejunum and ileum were significantly improved in 1,000 mg/kg treatment group (P < 0.01). 2) At 21 days of age, supplementation of 500 mg/kg AAE significantly increased the catalase (CAT) activity of small intestine, and the glutathione peroxidase (GSH-Px) activity of jejunum was improved (P < 0.01), meanwhile, the GSH-Px activity of duodenum and the total superoxide dismutase (T-SOD) activity of duodenum and jejunum were significantly higher than those of the control group (P < 0.05); supplementation of 1,000 mg/kg AAE significantly increased the CAT activity of duodenum and ileum and the GSH-Px activity of duodenum and jejunum (P < 0.05), and the ileum GSH-Px activity was significantly increased (P < 0.01); supplementation of 2,000 mg/kg AAE significantly increased the CAT activity of duodenum and ileum (P < 0.05). At 42 days of age, supplementation of 500 mg/kg AAE significantly increased the GSH-Px activity of ileum and the T-SOD activity of duodenum (P < 0.05), meanwhile, the T-SOD activity of jejunum was significantly increased (P < 0.01); supplementation of 1,000 mg/kg AAE significantly increased the CAT activity of jejunum and the T-SOD activity of ileum (P < 0.01), and the GSH-Px activity of jejunum was significantly increased (P < 0.05); supplementation of 2,000 mg/kg AAE significantly increased the T-SOD activity of ileum (P < 0.05), but significantly decreased the CAT activity of ileum and the GSH-Px activity of jejunum (P < 0.05). 3) The malondialdehyde (MDA) levels of 3 AAE supplementation groups were significantly decreased at 21 and 42 days of age (P < 0.05). The results suggested that dietary supplementation with AAE could improve the antioxidative capacity of small intestine in broilers.