Frequency of β-Casein Gene Polymorphisms in Jersey Cows in Western Japan

Nuomin,; Nguyen, Qui Dang; Aodaohu,; Nishino, Norikazu

doi:10.3390/ani12162076

Cited by 5 publications

(3 citation statements)

References 20 publications

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“…A1 and A2 caseins were prepared from Jersey cow milk. Exon 7 regions of the CSN2 gene were amplified and sequenced using genomic DNA purified from the buffy coat [ 12 ]. Using the milk of cows genotyped as A1A1 and A2A2, caseins were fractionated via conventional isoelectric precipitation (pH 4.6, 25 °C).…”

Section: Methodsmentioning

confidence: 99%

Modulatory Effects of A1 Milk, A2 Milk, Soy, and Egg Proteins on Gut Microbiota and Fermentation

Nuomin,

Baek,

Tsuruta

et al. 2023

Microorganisms

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Milk can be divided into A1 and A2 types according to β-casein variants, and there is a debate about whether A1 milk consumption exacerbates gut environments. This study examined the cecum microbiota and fermentation in mice fed A1 casein, A2 casein, mixed casein (commercial casein), soy protein isolate, and egg white. The cecum acetic acid concentration was higher, and the relative abundances of Muribaculaceae and Desulfovibrionaceae were greater in mice fed A1 versus A2 casein. The other parameters of cecum fermentation and microbiota composition were similar among the mice fed A1, A2, and mixed caseins. The differences were more distinctive among the three caseins, soy, and egg feedings. Chao 1 and Shannon indices of the cecum microbiota were lowered in egg white-fed mice, and the microbiota of mice fed milk, soy, and egg proteins were separately grouped by principal coordinate analysis. Mice fed the three caseins were characterized by a high abundance of Lactobacillaceae and Clostridiaceae, those fed soy were characterized by Corynebacteriaceae, Muribaculaceae, and Ruminococcaceae, and those fed egg white were characterized by Eggerthellaceae, Rikenellaceae, and Erysipelatoclostridiaceae. Thus, although several differences can arise between A1 and A2 caseins in terms of their modulatory effects on gut environments, the differences between milk, soy, and egg proteins can be more distinctive and are worth further consideration.

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Section: Methodsmentioning

confidence: 99%

Modulatory Effects of A1 Milk, A2 Milk, Soy, and Egg Proteins on Gut Microbiota and Fermentation

Nuomin,

Baek,

Tsuruta

et al. 2023

Microorganisms

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“…Amplification curves of the A1 alleles in A2A2 milk mixed with A1A1 milk at different ratios (0%, 1%, 2%, 3%, 10%, and 15%). conventional milk; therefore, increased consumer demand is expected for dairy products and Japanese dairy farmers are also encouraged to produce A2 milk (Nuomin et al, 2022). To distribute A2 milk to the market, it is necessary to certify that A2 milk is not contaminated with A1 milk, as there is a risk of contamination occurring during the processing of the milk.…”

Section: The Detection Limit Of the A1 Allele Was 2%mentioning

confidence: 99%

A highly sensitive PCR method for A1 allele detection in A2 milk samples without DNA isolation

Watanabe

Munakata

Muto

et al. 2023

Animal Science Journal

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We previously developed a genotyping method to detect the A1 and A2 alleles of the bovine β‐casein gene. This method required DNA extraction from hair samples. Recently, demand for A2 milk (milk from cows homozygous for the A2 allele) has increased, and dairy farms are required to have certification to produce A2 milk. Here, we describe the development of a new, simple, and sensitive genotyping method for the β‐casein gene that does not require DNA extraction. This method uses the CycleavePCR technique and can amplify the β‐casein gene directly from raw milk samples. Genotypes obtained from the milk samples (n = 27) were completely coincident with those obtained from genomic DNA. In addition, this method could quantify the A1 allele in the milk samples. The limit of detection for the A1 allele in A2 milk was 2%. The copy numbers of the A1 allele corresponding to the 2% detection limit were estimated to be 30.5 ± 24.3 molecules/μL. These findings indicate that this new genotyping method is simple and fast for detecting the A1 allele in milk samples and can therefore be potentially used to certify A2 milk.

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“…A1A1, A1A2 and A2A2 are the three important genotypes of milk-producing cow breeds worldwide with an average frequency of 0.112, 0.434 and 0.454, respectively for n = 7667 (Nuomin et al ., 2022). A recent study by Şahin and Boztepe (2023) conducted in Italy also found an average frequency of 0.145, 0.46 and 0.395 of A1A1, A1A2 and A2A2 genotypes, respectively for n = 400.…”

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confidence: 99%

Comparative evaluation of A1A2 and A2A2 cow milk-containing diets on biochemical and histological parameters of Wistar rats

Semwal,

Kumar,

Semwal

et al. 2023

Journal of Dairy Research

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This Research Communication aims to compare the effect of A1A2 and A2A2 cow milk diets on the biochemical and histological parameters of rats. The rats were divided into four groups and fed with a normal diet, A2 milk powder, A1A2 or A2A2 cow milk diets for 90 d. Blood glucose, kidney function, liver function and lipid profile were examined during the experimental period. The study showed an increase in the body weight of the A1A2 group whereas a slight decrease in the A2A2 group, and blood glucose levels increased from d 0 to day 90 in all experimental groups. However, none of these changes were found to be statistically insignificant (P > 0.05). Moreover, no significant changes were recorded in other parameters (serum glutamic pyruvic transferase and serum glutamic-oxaloacetic transaminase for liver function, bilirubin direct, cholesterol, triglycerides, creatinine and uric acid). The histology of the liver, kidney and pancreas also showed no changes in all groups. Overall, this study revealed no significant difference in the nutritional values of A1A2 and A2A2 milk types and hence equally beneficial for health. Although the present study showed no significant difference in the effect of both milk types in 90 d, further studies might be conducted to evaluate their longer term effects.

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Frequency of β-Casein Gene Polymorphisms in Jersey Cows in Western Japan

Cited by 5 publications

References 20 publications

Modulatory Effects of A1 Milk, A2 Milk, Soy, and Egg Proteins on Gut Microbiota and Fermentation

Modulatory Effects of A1 Milk, A2 Milk, Soy, and Egg Proteins on Gut Microbiota and Fermentation

A highly sensitive PCR method for A1 allele detection in A2 milk samples without DNA isolation

Comparative evaluation of A1A2 and A2A2 cow milk-containing diets on biochemical and histological parameters of Wistar rats

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