Animal Feed Science and Technology最新文献

This study has investigated the effect of the integration of wheat distillers, without solubles, after lipid extraction (RF-DDG) in a diet based on high-quality forages in partial substitution of human-edible feeds, i.e. corn and soybean meal (SBM), on milk production and quality, feed conversion efficiency and on the human-edible feed conversion efficiency of high producing dairy cows. The experiment was conducted on a commercial dairy farm for an 8-wk period, split into 2 periods, lasting 28 d each (2-wk adaptation and 2-wk experimental period with data collection) on 180 Holstein cows (averaging 130 DIM and 42.0 kg of milk/d at the start of the trial), randomly assigned to 4 pens (45 cows each). The cows, stratified by DIM, were split in two groups assigned two diets that differed according to the human edible feed inclusion: (1) a control diet (CON), based on alfalfa silage, grass silage, high moisture ear corn silage, and soybean meal (SBM) as a protein supplement, 2) a treatment diet (TREAT), in which the control diet was modified using RF-DDG at 13.0 % (dry matter basis) to totally replace soybean meal (SBM).

The dry matter intake was similar across treatments, whereas the milk yield was 2.06 kg/d lower for the TREAT diet. The inclusion of wheat RF-DDG increased the milk fat concentrations (3.74 vs 3.54 %) and decreased the milk protein concentration (3.02 vs 3.18 %), milk protein yield (1.19 vs 1.31 kg/d), and milk urea nitrogen (3.63 vs 7.61 mg/dL). Cows fed the TREAT diet showed an increased aNDFom, ADF ADL, NDIN and ADIN intake compared with those fed the CON diet. The TREAT diet resulted in a reduced milk yield as well as a reduced milk protein concentration and yield, which were likely caused by a reduction in the apparent digestibility of the protein and by different essential AA and RDP contents in the TREAT diet compared to the control DIET. The TREAT diet also decreased serum glucose, albumin, as well as the urea nitrogen and total protein in the blood, compared with the CON diet. Furthermore, the TREAT diet led to a reduction in the milk production feed conversion efficiency (in terms of milk yield/DMI and FPCM/DMI) and in the nitrogen utilization of the milk production (28.3 vs 31.0 %). The inclusion of RF-DDG led to a substantial increase in the human-edible feed conversion index for the protein (1.19 vs. 0.74) and for energy (1.66 vs 1.39), thereby improving the net protein and energy food balance. It has been concluded that further research is needed to find an economical process to extract oil from DDG without causing any further thermal stress that could compromise the protein components and amino acid supply of RF-DDG.

Branched-chain amino acids (BCAAs), including leucine (Leu), isoleucine (Ile), and valine (Val), are a class of amino acids that ruminants are incapable of synthesizing on their own. Available studies confirm that BCAAs and their metabolites play a key role in ruminant physiological processes, such as gastrointestinal digestion and absorption, tissue metabolism, mammary gland development, and immune system functions. However, there is a lack of comprehensive systematic reviews on this topic. Therefore, this paper briefly describes the metabolic characteristics and bioavailability of BCAAs in ruminants, and focuses on the role of BCAAs as functional amino acids, discussing the effects and mechanisms of BCAAs on ruminant physiological functions. Additionally, this paper points out the differences and limitations in the current BCAAs research based on data from all relevant ruminant trials from 2000 to the present. The findings and insights of this review can guide future research to optimize the level and mode of BCAAs supplementation in ruminant feeding programs.

Copper (Cu) is a critical limiting factor in grazing livestock production in Inner Mongolia. This study investigated the effects of Cu-deficient and Cu-supplemented diets on production metrics, nutrient digestion and absorption, ruminal microbiota, and metabolites in grazing Mongolian sheep. A total of 28 individually-housed Mongolian sheep were randomly assigned to a Cu-deficient feeding group (LCu) and a Cu-deficient feeding control group (LCG), supplemented with a multi-nutrient salt containing 0 mg Cu and 14.3 mg Cu, respectively, for 53 continuous days. Following this, a 7-day digestion test was conducted, after which seven sheep from each group were randomly slaughtered. The remaining sheep in LCu and LCG transitioned to a Cu-supplemented feeding group (SCu) and a Cu-supplemented feeding control group (SCG), receiving multi-nutrient salts with 43.0 mg Cu and 14.3 mg Cu, respectively. This phase entailed a 34-day diet acclimatization period, a 7-day digestion test, and eventual slaughter. The LCu diet significantly decreased the ruminal Cu and sulfur (S) content, as well as Cu apparent absorbability, compared to the LCG group (P<0.05). Conversely, SCu significantly increased the ruminal Cu content and the apparent absorbability of phosphorus (P), S, potassium (K), calcium (Ca), manganese (Mn), iron (Fe), Cu and zinc (Zn) compared to the SCG group (P<0.05). Amplicon sequencing analysis revealed a significant downregulation of Alistipes and Barnesiella (P<0.05) in the LCu group. Metabolomic analyses supported an elevation in ruminal citrulline and L-ornithine levels, affecting amino acid metabolic pathways in the LCu group (P<0.05). In the SCu group, there was a significant increase in the relative abundance of Saccharofermentans and Ruminococcus (P<0.05), with metabolomic analysis revealed elevated levels of nucleic acid and purine analog affecting purine metabolic pathways (P<0.05). Notably, neither treatment had a significant impact production metrics, rumen fermentation parameters, or the apparent digestibility of crude protein, acid detergent fiber and neutral detergent fiber (P>0.05). In conclusion, a Cu-deficient diet impairs Cu absorption and nutrient catabolism in grazing Mongolian sheep, while Cu supplementation effectively alleviated these deficiencies and enhances the absorption of various minerals.

Current gestating sow feeding strategies are based on using a single diet regardless of parity or gestation stage. Precision feeding (PF) of the individual sows allows dynamic changes in amino acid and energy requirements throughout gestation. The hypothesis of the study was that meeting the daily predicted amino acid and energy demands of gestating sows using a mathematical model and automatic precision feeder to establish the nutrition programs, would improve reproductive and productive performance compared to conventional feeding programs. Seventy-five mixed-parity sows were distributed among 3 treatments. A treatment managed as flat curve (FLAT: 2.1 kg/d, 1 – 110 d), a high-low-high curve (HLH: 2.2 kg/d, 1 – 49 d; 2.0 kg/d, 50 – 84 d; 2.6 kg/d, 85 – 110 d), where sows received the same diet with 3.2 Mcal/kg of metabolizable energy (ME) and 0.7 g/kg of standardized ileal digestible (SID) lysine. For the PF treatment, feeding level and blend of 2 basal diets (3.0 Mcal/kg of ME; 8.0 and 2.0 g/kg of SID lysine for high and low lysine, respectively) was adjusted daily for each sow to accurately meet estimated amino acid and energy requirements based on live weight, gestation stage and parity. Sows fed PF were heavier on d 110 of gestation (P = 0.011) and tended to increase total number of born (P = 0.092) and born alive (P = 0.077). Sows fed PF showed a higher litter weight (P = 0.003) at birth, lower lactation feed intake (P = 0.010), higher milk yield (P = 0.043) and a larger litter size (P = 0.050). Precision feeding sows also presented an improved maternal transformation index (P = 0.013) when compared to HLH and FLAT. In conclusion, our results demonstrate that the application of PF strategies based on daily nutrient adjustments is highly beneficial for high-producing sows to support the dynamic needs for nutrient availability for the sow´s body growth, mammary gland and fetal development.

The objective of this study was to evaluate the effects of harvest date in the first regrowth cycle and grass species on intake, in vivo digestibility and its relation to protein utilization in wethers fed timothy or tall fescue silages. Timothy and tall fescue were harvested at regular (RTI and RTF, respectively) or late date (LTI and LTF, respectively) in the first regrowth, creating four experimental silages. Eight wethers were used in a duplicated 4 × 4 Latin square. Experimental periods lasted for 4 wk and wethers were fed ad libitum during the first 3 wk, with intake recorded during the third week. During the fourth week, wethers were fed 80% of ad libitum, and feces and urine were collected during the last 4 d. Wethers receiving RTI showed the greatest DM intake when expressed as kg/d or as percentage of body weight (BW) (P≤0.05). The intake of neutral detergent fiber (aNDFom) was affected by forage species only, where animals fed timothy silages had greater aNDFom intake than animals fed tall fescue silages (P<0.001). Intakes of CP and sum of the protein fractions A, B₁ and B₂ (AB₁B₂) were affected by the interaction between harvest date and forage species, where wethers fed RTI showed the greatest intakes of CP (P=0.001) and AB₁B₂ (P=0.02). Harvesting the forages at late date decreased the in vivo digestibility in wethers but only for timothy, where animals fed LTI silage showed the lowest DM (P<0.001), organic matter (OM) (P<0.001), aNDFom (P=0.02) and acid detergent fiber (P=0.004) digestibility, and a tendency for lower CP digestibility (P=0.07) compared with the other silages. Wethers fed RTI silage showed greater intake of nitrogen (N) (P=0.001) and digestible OM (P=0.003), greater allantoin (P=0.03) and hippuric acid (P=0.05) excretions, greater microbial N flow (P=0.03), and a tendency for greater excretion of fecal N (P=0.09) compared with the other silage-fed animals. In conclusion, delayed harvest decreased in vivo digestibility only in timothy, but even with lower in vivo digestibility wethers fed timothy silages showed a greater intake than wethers fed tall fescue silages, likely due to lower concentration of hydroxycinnamic acids observed in timothy compared with tall fescue as published previously.

Effects of dietary dextrin at inclusion levels of 14.7 %, 20.7 %, 26.7 %, 32.7 % and 38.7 % on growth performance, feed utilization, biochemical composition, digestive enzyme activity, antioxidant capacity and tissue structure of Onychostoma macrolepis (1.78±0.10 g) was evaluated, the trial was conducted for 56-day. The results revealed that final body mass, weight gain and protein efficiency ratio were the highest in the 26.7% group, while feed conversion ratio (FCR) was the opposite. The optimal values of FCR and specific growth rate (SGR) were 25.27 % and 25.67 % respectively based on the quadratic regression analysis. The hepatopancreas trypsin activity was the lowest in the 32.7 % group (P<0.05), while the lipase activity in the 14.7 %, 20.7 %, and 26.7 % groups were higher than remaining groups (P<0.05), however, the amylase activity was not affected (P>0.05). Only the crude protein of whole fish was affected, its content was the highest in the 32.7 % group. Hepatopancreas and muscle glycogen were the highest in the 26.7 % group (P<0.05). Combined with the systematic clustering average method was found that MUFA and SFA in hepatopancreas increased, and n-6 PUFA and MUFA in muscle and MUFA in abdominal fat decreased with dextrin levels. The hepatopancreas glutathione peroxidase activity in the 32.7 % group was the lowest and catalase activity in the 20.7 % group was the highest (P<0.05), total superoxide dismutase activities in the 14.7 %, 20.7 % and 26.7 % groups were significantly higher than remaining groups (P<0.05), and malonaldehyde content in 38.7 % group reached the highest (P<0.05). Hepatopancreas exhibited severe vacuolation in the 32.7 % group, and intestinal villi were the longest in the 26.7 % group (P<0.05). In summary, based on FCR and SGR, the optimal dextrin levels in Onychostoma macrolepis feed were 25.27 % and 25.67 % respectively. When having good growth and not negatively affecting health status, the recommended addition levels of dextrin in feed were 20.7–26.7 %.

Pregnancy toxemia (PT) is the most frequent metabolic disorder for ewes in late pregnancy. Although propylene glycol (PG) and glycerol (GLY) are common glycogenic supplements for treating PT in ewes, the relative benefit of these supplements is not clear. In a previous study, it was demonstrated that PG was mainly effective in reducing the β-hydroxybutyrate acid (BHB) concentration, whereas GLY was more effective in increasing the plasma glucose concentration. Therefore, the objectives of the present study were to determine the effects of drenching various doses and combinations of PG and GLY to late-pregnant ewes in order to obtain a simultaneous increase in glucose and a decrease in BHB. Sixty-six multiparous Afec-Assaf ewes bearing at least two fetuses were used in 3 consecutive experiments. In all experiments, blood samples were collected twice before drenching (at 0630 and 0645 h), then the ewes were drenched with each supplement at 0700 h, and blood samples were taken every hour for 12–14 h post-drenching. In experiment 1, ewes were drenched either with 1) Control (CTL1, n = 6) – 55 mL water, 2) PG100 (n = 6) – 106 mL of PG, 3) GLY100 (n = 6) –108 mL of Koforin (containing 80 % glycerol, 15 % water, and 5 % ash), 4) PG50 (n = 6) – 53 mL of PG, and 5) GLY50 (n = 6) – 54 mL of Koforin. The plasma glucose concentration was higher after the GLY50 (P = 0.03) and GLY100 (P = 0.01) treatments than in CTL1. The plasma BHB concentration was lower after the PG50 (P = 0.001) and GLY50 (P = 0.02) treatments and tended to be lower in the PG100-treated ewes (P = 0.10) than in the CTL1 ewes. In experiment 2, ewes were drenched with 1) Control (CTL2, n = 6) –55 mL water, 2) MIX50 (n = 6) –26.5 mL PG + 27 mL Koforin, and 3) MIX100 (n = 6) –53 mL PG + 54 mL Koforin. No differences were observed among treatments for the main blood metabolites. In experiment 3, ewes were drenched with 1) Control (CTL3, n = 6) – 110 mL water, 2) MIX200(1:1) (n = 6) –106 mL PG +108 mL Koforin, and 3) MIX200(3:7) (n = 6) – 63.4 mL PG +150.6 mL Koforin. The plasma glucose concentrations were 17.8 % and 20.9 %, respectively, higher in the MIX200(1:1) and MIX200(3:7) ewes than in the CTL3 ewes (P < 0.01). The plasma BHB concentrations in the MIX200(1:1) and MIX200(3:7) ewes were 42 % and 47 %, respectively, lower than in the CTL3 ewes (P < 0.03). The NEFA concentration in the MIX200(1:1) and MIX200(3:7) ewes was 60 % and 57 %, respectively, lower than in the CTL3 ewes (P = 0.008). In conclusion, MIX200(1:1) and MIX200(3:7) were the most effective approaches to increasing glucose and reducing the BHB and NEFA concen