Document Type : Research Paper

Authors

• Hamidreza Taghian ¹
• kamran rezayazdi ¹
• Mehdi Dehghan banadaky ¹
• Hamed Khalilvandi-Behroozyar ²

¹ Department of Animal Science, Faculty of Agriculture and Natural Resources, University of Tehran, Karaj, Iran

² Department of Animal Sciences, Faculty of Agriculture, Urmia University, Urmia, Iran

Abstract

Keywords

• emulsifier
• bile powder
• lecithin
• fat
• dairy cow

Main Subjects

• Animal Nutrition and poultry

Extended Abstract

Introduction

    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.

Material and method

    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.

Results and discussion

    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.

Conclusion

    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.

Author Contributions

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All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.

Data Availability Statement

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Acknowledgements

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The authors would like to thank all participants of the present study.

Ethical considerations

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.

Conflict of interest

The author declares no conflict of interest.

Conflict of interest

The author declares no conflict of interest.