نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه علومدامی، دانشکدگان کشاورزی و منابع طبیعی، دانشگاه تهران، کرج، ایران
2 گروه علومدامی، دانشکده کشاورزی، دانشگاه ارومیه، ارومیه، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
This research aims to investigate the effect of a feeding fat supplement containing an additive (lecithin or bile powder) with the physical form of flake or granule on the apparent digestibility of nutrients and some blood parameters in Holstein dairy cows. 48 lactating cows were used during two experimental periods in a 2x3x2 completely randomized factorial design and randomly grouped into 6 experimental treatments: 1. Control diet + 2.5% granulated fat supplement, 2. Control diet + 2.5% granulated fat supplement containing 5% lecithin 3. Control diet + 2.5% granulated fat supplement containing 5% bile powder 4. Control diet + 2.5% Flaked fat supplement 5. Control diet + 2.5% Flaked fat supplement containing 5% lecithin and 6. Control diet + 2.5% Flaked fat supplement containing 5% bile powder. All the experimental diets were balanced according to the recommendations of the National Research Association. All data were analyzed by statistical software. The addition of lecithin or bile powder average milk production, ECM, 3.5% FCM, milk fat, protein, lactose, solids, solids nonfat, SCC, denovo fatty acids, mixed fatty acids, preformed fatty acids, saturated fatty acids, unsaturated fatty acids, mono unsaturated fatty acids, poly unsaturated fatty acids, stearic acid, palmitic acid and oleic acid (P ≥ 0.05). The addition of emulsifiers to the fat supplement of the high-production dairy cow diet may have positive effects on the production performance, milk compositions and source of fatty acids.
کلیدواژهها [English]
Extended Abstract
Energy requirements in dairy cows have elevate as milk production increases, normally fat supplements are used to help meet these energy requirements. Therefore, the amount of fatty acids intake increases due to the consumption of fat supplements and the increase in dry matter intake. According to the nutritionist recommendations, feeding more than 3 % of fat based on the dry matter intake should be provided from by-pass sources (neutral fat supplements). Presumably, one of the potential strategies to improve production performance and milk composition in dairy cows is supplementing emulsifying agents to the diet, because the reason for the decline in production performance and milk composition, especially fat and protein, is the reduction in absorption of fatty acids due to the increase duodenal flow of fatty acids which decrease availability of lysolecithin and micelles formation. In this regard, the saturation of the absorption sites of fatty acids in the jejunum and the mechanisms of adaptation by cows to maintain the stability of fatty acids composition in milk and tissues have also been reported. The most available source of these emulsifying compounds is soy lecithin, which is widely used in various industries. It is thought that the phospholipids fermentation in the rumen prevents their role as an emulsifier in the intestinal environment and subsequently cannot reveal positive effects on the production performance of the lactating dairy cow. Bile acids play an important role in the digestion and absorption of fats and fat-soluble vitamins and are the basis for improving metabolism and as a result increase the efficiency of the animal production, so this study investigated the effect of the physical form of the saturated fat supplement containing lecithin or bile powder on production performance, milk compounds and sources of fatty acids of the milk in high-producing Holstein cows.
48 lactating Holstein cows (lactation: 130±21; milk production: 38.4±1, weight: 590±12) during two experimental periods (24 cows in each period) in a 2x3x2 completely randomized factorial design used and were randomly grouped into 6 experimental treatments by using silver saturated fat supplement (Kimia Danesh Alvand ©, Qom, Iran): 1. Control diet + 2.5%granulated fat supplement, 2. Control diet + 2.5% granulated fat supplement containing 5% lecithin 3. Control diet + 2.5% granulated fat supplement containing 5% bile powder 4. Control diet + 2.5% Flaked fat supplement 5. Control diet + 2.5% Flaked fat supplement containing 5% lecithin and 6. Control diet + 2.5% Flaked fat supplement containing 5% bile powder. All the experimental diets were balanced to have the same amount of nitrogen and energy and met the nutrient requirements of the animals according to the recommendations of the National Research Association. To prepare the bile powder, the gallbladders were collected from the slaughtered and transferred to the laboratory, then homogenized and filtered through nylon filters, and then the bile powder was obtained by drying at 60°C for 24 hours. After the analysis of DM and nutrient content in the feed samples were measured Eventually, all test data were analyzed by using SAS statistical software and MIXED procedure. Milk production of each cow was recorded 3 time in 24 h in the last 7 days of both periods, and 50 mL milk sample was obtained. The samples were transferred to the refrigerator at 4° C, immediately after adding 0.1 g of potassium dichromate. To determination of protein, fat, lactose, solids, solids without fat, somatic cell count, urea nitrogen, Denovo fatty acids, mixed fatty acids, preformed fatty acids, saturated fatty acids, unsaturated fatty acids, mono unsaturated fatty acids, poly unsaturated fatty acid, palmitic acid, stearic acid, and oleic acid, samples were transferred to Alborz Milk Laboratory (Karaj, Alborz, Iran) and then analyzed with CombiScope device (FTIR 600 HP). The body weight and body condition score, were assigned weekly after milking in the morning and before feeding morning meal, and at the same time, the BCS was determined by two experts using standard index of 1 to 5.
The addition of lecithin or bile powder enhanced average milk production, ECM, 3.5% FCM, milk fat, protein, lactose, solids, solids nonfat, SCC, denovo fatty acids, mixed fatty acids, preformed fatty acids, saturated fatty acids, unsaturated fatty acids, mono unsaturated fatty acids, poly unsaturated fatty acids, stearic acid, palmitic acid and oleic acid (P ≥ 0.05). It seems influencing factors on production performance and milk composition in lactating dairy cows fed with emulsifying compounds, are: stage of lactation, amount and the type of fat supplement, the ratio between stearic, palmitic and oleic acids in the fat supplement, the amount and type of emulsifying compounds added to the fat supplement and protection method for emulsifying compounds against rumen fermentation in fat supplements.
Adding emulsifying compounds to fat supplements in the diet of dairy cows improved production performance and some milk compounds, although their physical form did not demonstrate positive or negative effects in this study. Therefore, the results of this research suggest that the limitation of the emulsifying capacity of the intestinal environment is probably one of the reasons for the decrease in the absorption of fatty acids with the increase in the flow of fatty acids to the intestine. As a result, supplementing emulsifying agents in such a way that they are released after the rumen, probably improves the dairy cow production responses in the early and middle of the lactation period. Generally, more research is needed regarding the supplementation of emulsifying compounds with fat supplements containing different proportions of palmitic and stearic acids.
For research articles with several authors, a short paragraph specifying their individual contributions must be provided. The following statements should be used “Conceptualization, X.X. and Y.Y.; methodology, X.X.; software, X.X.; validation, X.X., Y.Y. and Z.Z.; formal analysis, X.X.; investigation, X.X.; resources, X.X.; data curation, X.X.; writing—original draft preparation, X.X.; writing—review and editing, X.X.; visualization, X.X.; supervision, X.X.; project administration, X.X.; funding acquisition, Y.Y. All authors have read and agreed to the published version of the manuscript.” Please turn to the CRediT taxonomy for the term explanation. Authorship must be limited to those who have contributed substantially to the work re-ported.
All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.
In this section, please provide details regarding where data supporting reported results can be found, including links to publicly archived datasets analyzed or generated during the study (see examples). Data available on request from the authors.
If the study did not report any data, you might add “Not applicable” here.
The Acknowledgments section should be a few sentences at the end, but it is important to recognize those people (organizations and individuals) who made considerable impact on the research, provided significant help to the author to formulate and complete the experiment, and improved the research at any stage (from providing access to equipment or field sites to editing the manuscript). However, this is an optional section.
In this section, you can acknowledge any support given which is not covered by the author contribution or funding sections. This may include administrative and technical support, or donations in kind (e.g., materials used for experiments).
The authors would like to thank all participants of the present study.
The study was approved by the Ethics Committee of the University of ABCD (Ethical code: IR.UT.RES.2024.500). The authors avoided data fabrication, falsification, plagiarism, and misconduct.
The author declares no conflict of interest.
The author declares no conflict of interest.
)