b-Lactoglobulin Variants in Awassi and Morkaraman Sheep and their Association with the Composition and Rennet Clotting Time of the Milk
In this study, b-lactoglobulin (b-Lg) variants in Awassi and Morkaraman sheep were studied using polyacrylamide gel electrophoresis, and their association with composition and rennet clotting time of the milk was estimated. Two alleles (A and B) and 3 different genotypes for b-Lg (AA, AB and BB) were observed in the whey from both breeds. The frequencies of b-Lg alleles were estimated as A 0.63 and B 0.37 in the Awassi breed, and A 0.56 and B 0.44 in the Morkaraman breed. These results indicate high b-A frequencies in both sheep breeds. Significant relationships were obtained between b-Lg variants and some properties of the milk from both sheep breeds (P < 0.01). In the Awassi breed, milks with b-Lg BB had significantly higher fat content and lower lactose content, while milks with the same variant had higher protein and solid non-fat contents in the Morkaraman breed. On the other hand, milks with the b-Lg AA variant in the Awassi breed had a short rennet clotting time, while milks with this variant in the Morkaraman breed had the lowest value for rennet clotting time but the result was not statistically significant. Therefore, it could be concluded that milks with the BB genotype are of importance in terms of cheese technology.
b-Lactoglobulin Variants in Awassi and Morkaraman Sheep and their Association with the Composition and Rennet Clotting Time of the Milk
In this study, b-lactoglobulin (b-Lg) variants in Awassi and Morkaraman sheep were studied using polyacrylamide gel electrophoresis, and their association with composition and rennet clotting time of the milk was estimated. Two alleles (A and B) and 3 different genotypes for b-Lg (AA, AB and BB) were observed in the whey from both breeds. The frequencies of b-Lg alleles were estimated as A 0.63 and B 0.37 in the Awassi breed, and A 0.56 and B 0.44 in the Morkaraman breed. These results indicate high b-A frequencies in both sheep breeds. Significant relationships were obtained between b-Lg variants and some properties of the milk from both sheep breeds (P < 0.01). In the Awassi breed, milks with b-Lg BB had significantly higher fat content and lower lactose content, while milks with the same variant had higher protein and solid non-fat contents in the Morkaraman breed. On the other hand, milks with the b-Lg AA variant in the Awassi breed had a short rennet clotting time, while milks with this variant in the Morkaraman breed had the lowest value for rennet clotting time but the result was not statistically significant. Therefore, it could be concluded that milks with the BB genotype are of importance in terms of cheese technology.
___
- King, J.W.B.: The distribution of sheep ß-lactoglobulin. Anim. Prod., 1969; 11: 53-57.
- Thomas, A.S., Dawe, S.T., Walker, R.A.: Milk protein polymorphism in Hyfer and Border Leicester X Merino sheep. Milchwissenschaft, 1989; 44: 686-688. 3. Lopez-Galvez, G., Amigo, L., Ramos, M.: Genetic polymorphism of whey proteins in two ovine breeds. Milchwissenschaft, 1994; 49: 123-125. 4. Aliev, G.A., Koloteva, R.S.: Genetic variation in the β-lactoglobulin in the milk of sheep. Doklady Vsesoyuznoi Akademii Sel’skokhozyaistvennykh Nauk, 1973; 4: 23-25.
- Erhardt, G.: Evidence for a third allele at the β-lactoglobulin (β- Lg) locus of sheep milk and its occurrence in different breeds. Anim. Genet., 1989; 20: 197-204.
- Recio, I., Fernandez-Fourner, A., Martin-Alvarez, P.J., Ramos, M.: β-lactoglobulin polymorphism in ovine breeds: Influence on cheese making properties and milk composition. Lait, 1997; 77: 259-265.
- Lopez-Galvez, G., Amigo, L., Ramos, M., Juarez, M.: Genetic polymorphism of milk proteins of various breeds of ewe. In: Brief Communications of the XXIII International Dairy Congress, Montreal, October 8-12, Vol. I. Brussels, Belgium; International Dairy Federation. 1990. 8. Esenbuğa, N.: The relationships between milk protein phenotypes and lactation properties, and growth characteristics of lamb. M.Sc. Thesis, Atatürk University, Natural and Applied Science, Erzurum, Turkey. 1995.
- Schmoll, F., Herget, I., Hatzipanagiotou, A., Tholen, E., Wimmers, K., Brem, G., Schellanger, K.: Association of β- lactoglobulin variants with milk production, milk composition and reproductive performance in milk sheep. Wiener Tieraerztl. Monats., 1999; 86: 57-60.
- Garzon, S.A., Martinez, H.J., Aparicio, R.F., Mendez, M.D., Montoro, A.V.: Relationship between β-lactoglobulin and technological indices in Manchega sheep. Archiv. Zootec., 1993; 42: 155-160.
- Lopez-Galvez, G., Ramos, M., Martin-Alvarez, P.J., Juarez, M.: Influence of milk protein polymorphism on cheese producing ability in the milk of Manchega sheep breed. In: Cheese yield and factors affecting its control. Brussels, Belgium; International Dairy Federation (pp. 163-173). 1994.
- Lopez-Galvez, G., Ramos, M., Martin-Alvarez, P.J., Juarez, M., Galvez, G.L., Alvarez, P.J.M.: Influence of milk protein polymorphism on cheese producing ability in the milk of Manchega ewes breed. Sheep Dairy News, 1998; 15: 35-36.
- Martinez, H.J., Garzon, S.A., Mendez, M.D., Aparicio, R.F., Vera, V.A.: Effect of β-lactoglobulin genetic variants on the pH, total casein concentration and yield of curd in Manchega sheep. Archiv. Zootec., 1993; 42: 245-252.
- Emsen, H.: The Principles of Animal Growth. Atatürk University Pub. no: 720, p 231. Erzurum, Turkey. 1997.
- Sawaya, W.N., Safi, W.J., Al-Shalhat, A.F., Al-Mohammad, H.M.: Studies on the chemical composition and nutritive value of sheep milk. Milchwissenschaft, 1984; 39: 90-93.
- Akbulut, O.: The researches on some yield traits of Awassi x Morkaraman crossbreeds. M.Sc. Thesis, Atatürk University, Natural and Applied Science, Erzurum, Turkey. 1986.
- Türkiye İstatistik Kurumu, 2002. Tarımsal Yapı. Ankara, Türkiye.
- Çelik, S., Özdemir, S.: Chemical composition and major minerals of Awassi sheep milk during lactation. Milchwissenschaft, 2003; 58: 373-375.
- Bech, A., Munk, K.S.: Studies on bovine milk protein polymorphism by electrofocusing in agarose gels containing 7M urea. Milchwissenschaft, 1988; 43: 230-232.
- FIL-IDF: Milk. Determination of total solids. Standard 21. Brussels: International Dairy Federation. 1962.
- FIL-IDF: Milk. Determination of the nitrogen content, Kjeldahl method. Standard 20B. Brussels: International Dairy Federation. 1993.
- Kurt, A., Çakmakcı, S., Çağlar, A.: A Guide Book of Analysis Methods of Milk and Milk Products. Atatürk University, Agricultural Faculty no: 18, p 238, Erzurum, Turkey. 1996.
- FIL-IDF: Milk. Determination of rennet clotting time. Standard 110A. Brussels: International Dairy Federation. 1987.
- Falconer, D.S., Mackay, T.F.C.: Introduction to Quantitative Genetics. Longman Group Ltd., p464, Harlow, England. 1996.
- Neter, J., Kutner, M.H., Nachtsheim, C.J., Wassern, W.: Applied Linear Statistical Models. The McGraw-Hill Companies, Inc., New York, USA, p 1408. 1999.
- Minitab Inc.: MINITAB®‚ Statistical Software Release 11.12. MINITAB Inc. Enterprise Drive, State College, PA 6801-3008, USA. 1996.
- Chiofalo, L., Micari, P., Girmenia, A.M.: Genetic polymorphism of β-lactoglobulin in Comisana ewes reared in Sicily. Scienza e Tecnica Lattiero-Casearia, 1987; 38: 104-114.
- Üçüncü, M.: A’ dan Z’ ye Peynir Teknolojisi (Cilt I). Meta Basım Matbaacılık Hizmetleri, 543s, İzmir, Turkey, 2004.
- Rampilli, M., Cecchi, F., Giuliotti, L., Cattaneo, T.M.P.: The influence of β-lactoglobulin polymorphism on protein distribution and coagulation properties in milk of Massese breed ewes. In: Milk protein polymorphism (pp. 311-315). Brussels, Belgium: International Dairy Federation. 1997.
- Pilla, F., Dell’Aquila, S., Taibi, L., Tripaldi, C., Puppo, S.A., Napolitano, F., Pallotta, M.L., Angelucci, M., Girolami, A.: Influenza del polimorfismo genetico della beta-lattoglobulina su alcune caratteristiche fisico-chimiche e tecnologiche del latte di pecora. In Atti. XI Congresso Nazionale. A.S.P.A., Grado, Italy (pp. 207-208). 1995.