CSN1S1 Genotypes Research Articles

CSN1S1 Genotype and the Effect of the F Allele on Milk Characteristics in Slovak White Shorthaired Goats

CSN1S1 Genotype and the Effect of the F Allele on Milk Characteristics in Slovak White Shorthaired Goats

CSN1S1 and LALBA Polymorphisms and Other Factors Influencing Yield, Composition, Somatic Cell Score, and Technological Properties of Cow's Milk.

We evaluated the influence of CSN1S1 and LALBA polymorphisms on cow's milk yield and quality. The analysis was done on Czech Simmental and Holstein cows. Non-genetic factors were included as well. CSN1S1 did not influence the milk performance in the first lactation. In the second lactation, cows with the BB genotype had significantly higher milk, protein, and fat yields than BC. The differences between LALBA genotypes were non-significant in the first lactation, while in the second lactation, the fat percentage was significantly higher in BB than in AB. The farm significantly influenced milk, protein, and fat yields in both the first and second lactations and fat percentage in the first lactation. The effect of CSN1S1 and LALBA genotypes on the milk technological quality was non-significant. Breed did not influence any of the evaluated technological traits and SCS. The ethanol test was not influenced by farm, season, lactation phase, protein percentage, breed, or non-fat solids percentage. Farm, season, and protein percentage significantly influenced milk fermentation ability, renneting, and SCS. The lactose content is a good indicator of udder health.

Single and combined effects of CSN1S1 and CSN2-casein genes on Awassi sheep milk quantity and quality.

Background and Aim:Milk produced from Awassi sheep is of high nutritive value; its production is relatively low in Awassi sheep, so the genetic improvement programs targeted milk production and its components are of high importance, especially when using genes that have an important signal to milk traits. This study was aimed at assessing the influence of alpha S1 (CSN1S1) and beta-casein (CSN2) genes genotypes interaction on Awassi ewes milk productivity.Materials and Methods:A total number of 391 milk yield and its composition records (taken through five consecutive years, 2007-2011) of 167 ewes were utilized for this study. DNA samples were extracted from the ewe’s blood samples, then the polymerase chain reaction products of alpha S1 (CSN1S1) and beta-casein (CSN2) genes were sequenced. The obtained sequences were analyzed; thereafter, the detected variants were tested for their possible association with milk traits.Results:The CSN1S1 and CSN2 variants allelic frequencies were 0.85 and 0.15, and 0.95 and 0.05, respectively. Lactose and solid not fat (SNF) % were associated with TC CSN1S1 genotypes. No association was found among CSN1S1 polymorphic genotypes with milk production, lactose, and SNF % were associated with TC CSN1S1 genotypes. Ewes of CSN2 AC genotype showed higher milk production traits, while no association was found between milk composition traits and CNS2 genotypes. Nevertheless, CSN1S1*CSN2 interaction showed the highest SNF, fat percentages, and milk production.Conclusion:The substantial interaction effects between CSN1S1×CSN2 genes were significantly affected the amount of milk, fat, and SNF% produced. The detected variants should be included in the breeding programs of Awassi sheep that are designed for improving their milk quantity and quality.

Relationships of αs1-casein (CSN1S1) and β-casein (CSN2) genotypes and their association with milk quality and coagulation properties in Bulgarian Brown cattle

The aim of the present investigation was to establish the relationships of αs1-casein (CSN1S1) and β-casein (CSN2) genotypes in Bulgarian Brown cattle and to evaluate their association with milk quality and milk coagulation properties. Milk proteins’ polymorphism was found out in 155 tissue samples from cows reared at 4 farms. Innovative protocols and techniques were used for determination of genetic polymorphism of αs1-casein (CSN1S1) and β-casein (CSN2) in Brown cattle. After collection, tissue samples were shipped to the University in Padova, Italy for PCR-RFLP analysis. The analysis of milk composition was done in the lab of the Agriculture Institute – Stara Zagora on Lactoscan ultrasound milk analyzer, whereas coagulation properties of individual milk samples were evaluated on a Computerized Renneting Metter – Polo Trade, Italy. During the study, the following parameters were studied: milk fat and protein contents (%), rennet coagulation time (RCT, min), curd firmness (а30, mm) and curd firming time (k20, min). Heterozygous cows for both studied milk proteins: CSN1S1 and CSN2, had higher milk fat and milk protein percentages, 4.71% fat and 3.45% protein in genotype ВС of CSN1S1 and 5.00% fat and 5.33% protein in genotype АВ of CSN2. The milk of cows from different CSN1S1 and CSN2 genotypes was outlined with moderate curd firmness and good coagulation time. Homozygous cows for both studied milk proteins had higher curd firmness (32.31 mm) for the ВВ genotype of CSN1S1 and 31.29 mm for the АА genotype of CSN2.

Oxidative Status of Goats with Different CSN1S1 Genotypes Fed ad Libitum with Fresh and Dry Forages.

Forty late-lactation Girgentana goats were used to study the effect of diets fed ad libitum and αS1-casein (CSN1S1) genotype on redox balance. The goats genotyped at CSN1S1 locus (A/A, A/F) were subjected to four feeding treatments different for percentage inclusion of dry and fresh forage: DAF100 (98% of Dry Alfalfa Forage), DAF65 (65% of Dry Alfalfa Forage), FSF100 (100% of Fresh Sulla Forage) and FSF65 (65% of Fresh Sulla Forage). Blood samples were analyzed for superoxide dismutase (SOD) and glutathione peroxidase (GPX) activity, reactive oxygen metabolites (ROMs), biological antioxidant potential (BAP) and non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA), albumin, glucose and cholesterol contents. The oxidative stress index (OSI) was calculated as percentage ratio of ROMs to BAP. Redox balance was improved by Sulla inclusion, as reflected in the lower OSI values found in FSF100 and FSF65 groups. DAF100 group displayed the highest GPX activity, while other groups exhibited the highest SOD activity. Fresh forage diets increased albumin concentration while no effect of tested factors was noted on glucose, NEFA, BHBA and cholesterol contents. The interaction diet × genotype was significant only for GPX activity. GPX and albumin were negatively correlated and were correlated positively and negatively with ROMs, respectively. Diet rather than genotype affects redox balance in dairy goats and a possible role of forage polyphenol compounds on oxidative status needs to be tested in future studies.

Goat Milk with Different Alpha-s1 Casein Genotype (CSN1S1) Fermented by Selected Lactobacillus paracasei as Potential Functional Food

The characteristics of fermented milk are affected by the type of milk used and the microorganisms involved in the fermentation process. Goat milk has been widely suggested as a possible alternative to cow milk in allergic subjects, because of the high genetic variability in alpha-s1 casein (CSN1S1) content, which is associated with different technological and nutritional properties of milk. The aim of the study was to evaluate the suitability of goat milk with low and high CSN1S1 to produce fermented milk. In addition, the performance as starter of selected Lactobacillus paracasei FS109 strain compared to no-selected L. paracasei strains was investigated. Initially, the selected L. paracasei FS109 strain was tested for adhesion ability to HT-29 and Caco-2 cells and immunomodulation effect. Then, the strain was used to produce fermented milk from goat milk with a low and high casein CSN1S1 genotype. The results indicated that greater acidifying activity was obtained for L. paracasei FS109 after 24 h of fermentation than the other two strains tested independently by the CSN1S1 genotype. L. paracasei FS109 grew well during fermentation, reaching a higher value (>8.5 log CFU/mL). Interestingly, the same strain maintained a high viable population (about 9 log CFU/mL) during the 30-day cold storage of the product. The present study shows for the first time the suitability of the goat milk with low CSN1S1 genotypes to produce fermented milk and highlight the importance of strain selection in determination of technological and beneficial traits. Combining goat milk with low CSN1S1 and selected strains could be a strategy of improving traditional and functional fermented milk market.

Non-parametric analysis of the effects of αS1-casein genotype and parturition non-genetic factors on milk yield and composition in Murciano-Granadina goats

Limited sample sizes imply parametric assumptions could be violated, even if traits have been reported to fulfil parametric assumptions. Parametric studies have addressed a non-significant influence of CSN1S1 genes on Murciano-Granadina milk yield, fat, protein and dry extract. We used non-parametric categorical tests to find alternative statistical methods to analyse the power to explain the variability found in the population regarding milk yield and its components. We analysed 2090 records for milk yield, and its components from 710 Murciano-Granadina CSN1S1-genotyped goats. Categorical regression equations were issued to predict which and at what level these factors may determine milk yield (kg), fat (kg), protein (kg) and dry extract (kg). All environmental (farm and parturition year) and animal-inherent factors (genotype, birth type and age) resulted statistically significant (p < .05) except for birth season and month. CSN1S1 genotype was highly statistically significant and explained from 8.3% to 9.2% of protein and fat content variability, resembling the values for highly selected French breeds. Seasonal peaks and lows resembled other breeds’. Heterozygote advantage of certain combinations of E allele with those alleles strongly or weakly influencing milk components and yield such as A, B, B2, F and homozygote BB genotype reported the highest statistically significant effects on milk components and yield. Our results suggest that non-parametric tests may report contextually valid results when having a large sample size is not possible. Selecting for certain CSN1S1 genotypes may promote the efficient production of better-quality milk in greater amounts, improving the international competitiveness and profitability of local breeds.HighlightsNon-parametric tests are crucial if normality and heteroskedasticity analyses fail.Murciano-Granadina milk traits compared with highly selected international breeds’.E allele combinations and BB reported highest effects on milk components and yield.

Association of the CSN1S1 gene polymorphism with milk composition traits in Jamunapari goat

The genetic polymorphism of the CSN1S1 (casein alpha-s1) locus was investigated in Jamunapari goat breed by Sodium Dodicyle Sulphate – Poly Acrylamide Gel Electrophoresis (SDS-PAGE) and Polymerase Chain Reaction – Restriction Fragment Length Polymorphism (PCR-RFLP). A total of 122 milk and blood samples were collected. The SDS-PAGE pattern revealed the presence of four variants of CSN1S1 locus namely, A, B, E and F. The A allele of a-s1 – casein was observed in the majority of goats. The genotypic frequency of the AA, BB, BE, AF and FF genotypes of CSN1S1 locus were 0.437, 0.175, 0.250, 0.125 and 0.012, respectively. The PCR-RFLP was performed, six different variant groups of F allele (224)bp, the B/E allelic pair (161+63) bp, A/0 allelic pair (150+63) bp, AD allelic pair (212+150+63) bp, AF allelic pair (224+150+63) bp and BF allelic pair (224+160+63) were obtained after restriction digestion with XmnI. The genotypic frequency of AA, AD, AF, BB, BE, BF and BC genotypes were 0.274, 0.114, 0.147, 0.098, 0.163, 0.081 and 0.163, respectively. The allelic frequency of A, B, C, D, E and F were 0.360, 0.303, 0.081, 0.057, 0.081 and 0.114, respectively. The present study showed that AA genotype had significant effect on total protein content on the milk and AD genotype had significant effect on 90 day milk yield in Jamunapari goat. Thus the CSN1S1 genotype information in Jamunapari could be utilised in selection strategies, in order to select genetic stock for the production of goat milk with higher protein content in marker assisted selection to increase the rate of genetic gain.

ALLERGENICITY ASSESSMENT OF GOAT'S MILK DIFFERENT EXPRESSIONS OF ALPHA S1-CASEIN IN PATIENTS ALLERGIC TO COW'S MILK

Background: Cow’s milk protein allergy (CMPA) is the most common food allergy, especially, in infants and young children. In this case, milk from other mammalian species has been suggested as a possible nutritional alternative to cow’s milk. Goat’s milk is used quite popular to replace for cow’s milk. In the goat species, αS1casein (αS1-CN), coded by the CSN1S1 gene, is characterized by qualitative and quantitative polymorphisms extensively. This aim of this study is to evaluate allergenicity of goat’s milk containing differentk kinds of αS1CN. Methods: Individual milk samples from 26 selected goats with different CSN1S1 genotypes were analyzed by SDS-PAGE and immunoblotting by using sera from children allergic to cow’s milk with IgE specific to CN and/or serum protein. Results: The absence of reactivity for the αs1-CN highlighted with immunoblotting for all goat milk samples. Conclusions: The goat’s milk with particular genotype for CSN1S1 could be used as a source protein alternative in the case of αs1-CN awareness. Furthermore, these tests could be useful for evaluating from time to time the reactivity of patients with CMPA against milk proteins of these goats selected to establish the safety of its use in the specific subject. Key words: Allergenicity, milk protein, goat, alphaS1-Casein, CSN1S1gene

Role of genetic variation of αS1-casein, lactation time and parity on milk production and composition of Zaraibi goats.

ABSTRACTThe aim of this study was to investigate the effect of CSN1S1 gene polymorphism, time of lactation and parity on milk quantity and quality. A total number of 165 Zaraibi goats (105 kids, 7 bucks and 53 does) after kidding season of February/ March 2013 were used in this experiment. The electrophoretic pattern of digested fragments of PCR amplified goat CSN1S1 products with XmnI enzyme showed the presence of 9 genotypes, 4 homozygous (AA, BB, CC and DD) and the other 5 heterozygous (AC, AD, BC, BD and CD). The nine genotypes were derived from 4 alleles; three strong alleles (A, B and C) with frequencies (17.76, 27.63 and 26.97%, respectively) and one intermediate allele (D) with frequency 27.63%. BB and CC were the most common homozygous genotypes detected in the present study with similar frequency (18.42%) followed by DD (17.76%), BD (13.82%), AA (10.53%), AC (10.53%), BC (4.61%), AD (3.95%) and CD (1.97%). Daily milk yield, percentage of milk fat, protein, total solid and solid not fat significantly affected by CSN1S1 genotypes. Zaraibi does carrying AD variant showed the highest levels of daily milk yield, fat, protein, total solid and solid not fat. Sequence analysis showed that only the deletion of nucleotide C in allele A caused substitution of TTC to TTG forming Leu (Leucine) instead of Phe (Phenyl alanine) in mature protein. Meanwhile, no polymorphism detected between nucleotide 1 and 274 at amplified sequence of exon 9, so this region is considered as a highly conserved among alleles (A, B, C and D).Daily milk yields in Zaraibi does were significantly high at the first week after kidding, peaked at the 2nd week then decrease till the end of lactation. Moreover, the highest milk yields were recorded in does at the 7th and 6th parities, while the lowest values observed in does at the 1st and 2nd parities. In addition, percentages of fat and total solids were the highest at day 90 (end of suckling period) than during days 120 and 210 of lactation period. Milk protein was the highest at end of lactation (day 210), while lactose levels showed the lowest values. In conclusion, studying genetic polymorphism for Zaraibi goats CSN1S1 gene is important for identifying favorable genotypes associated with high milk yields, protein and fat. Breeding program would be changed toward selecting animals carrying the strong and mild alleles for milk protein and fat required for economic goat milk industry.

Short communication: Predictive ability of Fourier-transform mid-infrared spectroscopy to assess CSN genotypes and detailed protein composition of buffalo milk

The aim of this work was to test the applicability of Fourier-transform mid-infrared spectroscopy (FT-MIR) for the prediction of the contents of casein (CN) and whey protein fractions in buffalo milk. Buffalo milk samples spectra were collected using a MilkoScan FT2 (Foss, Hillerød, Denmark) over the spectral range from 5,000 to 900 wavenumber × cm−1. Contents of protein fractions, as well as CSN1S1 and CSN3 genotypes, were assessed by reversed phase HPLC. The highest coefficients of determination in cross-validation (1 − VR) were obtained for the contents (g/L of milk) of total protein and CN (1 − VR=0.92), followed by the content of β-CN, total whey protein, and αS2-CN (1 − VR of 0.87, 0.77, and 0.63, respectively). Conversely, contents of αS1-CN, γ-CN, glycosylated-κ-CN, total κ-CN, and whey protein fractions were predicted with poor accuracy (1 − VR <0.51). When protein fractions were expressed as percentages to total protein, 1 − VR values were never greater than 0.61 (β-CN). Only 56 and 70% of the observations were correctly classified by discriminant analysis in each of 2 groups of CSN1S1 and CSN3 genotypes, respectively. Results showed that FT-MIR spectroscopy is not applicable when prediction of detailed milk protein composition with high accuracy is required. Predictions may play a role as indicator traits in selective breeding, if the genetic correlation between FT-MIR predictions and measures of milk protein composition are high enough and predictions of protein fraction contents are sufficiently independent from the predicted total protein content.

Effect of the αs1-casein genotype and its interaction with diet degradability on milk production, milk quality, metabolic and endocrinal response of Girgentana goats

A study was carried out to evaluate if diets at different starch and protein degradability could influence productive, metabolic and hormonal response of goats at different αs1-casein genotype. Nineteen Girgentana goats at mid lactation were selected on the basis of their genotype at αs1-casein locus: nine goats homozygous for strong (AA) alleles and ten goats homozygous for weak alleles (FF). The goats were used in a 2×2 factorial arrangement of treatments, with two genotypes (AA, FF) and two diets at different degradability (H diet: RDP, 60.5% of crude protein; starch degradability, 78,4%; L diet: RDP, 50.9% of crude protein; starch degradability, 66.8%). The dry matter intake was not affected by αs1-genotype (respectively AA and FF goats: 2107 and 2086g/d; P=0.160), whereas it resulted significantly higher when goats were fed with the L diet (2130g/d vs 2063g/d; P<0.001). Milk yield was much higher in AA compared to FF goats (1401 g/d vs 1076 g/d; P=0.03). As expected, milk protein and casein resulted significantly higher and urea resulted significantly lower in AA goats (protein, 3.72% vs 3.20%; P<0.001; casein, 3.11% vs 2.56%, P<0.001; urea 56.6mg/dl vs 69.2mg/dl, P<0.001) whereas no differences were found, between genotypes, in milk fat and lactose. No diet effect was detected on milk production and composition. The αs1 genotype has strongly influenced free triiodothyronine (fT3) levels, which were higher in AA goats (1.64 vs 1.37ln+1pg/ml; P=0.009). No other differences were evident between genotypes or diets. In conclusion, the hypothesis that diets at different degradability could modify the productive response of goats at different CSN1S1 genotype has not been demonstrated. It has not been clarified the metabolic and endocrinal mechanisms involved in the manifestation of the differences found in relation to the studied polymorphism.

Mediterranean river buffalo CSN1S1 gene: search for polymorphisms and association studies

The aim of the present study was to investigate the variability at CSN1S1 locus of the Italian Mediterranean river buffalo and to study possible allele effects on milk yield and its composition. Effects of parity, calving season and month of production were also evaluated. Three single-nucleotide polymorphisms were detected. The first mutation, located at position 89 of the 17th exon (c.628C&gt;T), is responsible for the amino acid change p.Ser178 (B allele)/Leu178 (A allele). The other two polymorphisms, detected at the positions 144 (c.882G&gt;A) and 239 (c.977A&gt;G) of 19th exon, respectively, are silent (3ʹ UTR, untranslated region). Associations between the CSN1S1 genotypes and milk production traits were investigated using 4122 test day records of 503 lactations from 175 buffalo cows. Milk yield, fat and protein percentages were analysed using a mixed linear model. A significant association between the c.628C&gt;T SNP and the protein percentage was found. In particular, the CC genotype showed an average value ~0.04% higher than the CT and TT genotypes. The allele substitution effect of cytosine into thymine was –0.014, with a quite low (0.3%) protein percentage contribution to total phenotypic variance. A large dominance effect was detected. Characterisation of the CSN1S1 transcripts and a method based on MboI amplification created restriction site PCR for a rapid genotyping of c.628C&gt;T are provided.

Goat alpha-s1 casein genotype interacts with the effect of extruded linseed feeding on milk fat yield, fatty acid composition and post-milking lipolysis

This study compares two groups of 23 and 24 goats with different CSN1S1 genotypes, matched for lactation number and stage. During the first experimental period (4 weeks) half of the goats of each genotype received the control diet (CT) and the second half received a similar diet containing extruded linseed (EL diet). During the second experimental period, the two groups of goats were switched from the CT to the EL diet and from the EL to the CT diet, respectively. Results confirm the lower milk protein (−4.8g/kg) and fat (−6.5g/kg) concentrations in the low genotype group, whereas milk yield was slightly higher (+0.49kg/d) and lactose concentration was unchanged. Between the genotype groups, there were differences in milk fat proportions of at least 25 FAs, particularly the C7 to C13 saturated FAs and C16:0, C18:0, C18:2n-6 and cis9,trans11-C18:2 acids. In addition, delta-9 desaturation ratios were higher in the low CSN1S1 group for C10:0, C14:0, C18:0, trans11-C18:1 and trans13-C18:1. This strongly suggests an effect on mammary delta-9 desaturase activity, especially for C18:0 and trans11-C18:1. It is likely that higher desaturation ratios in the low genotype, as well as observed changes in other FAs, could compensate for the lower synthesis of medium-chain FAs (C7:0–C13:0), thus contributing to maintenance of the melting point of milk fat in this genotype. The effect of the EL diet on milk FA proportions was highly significant for almost all FAs, along with increased milk fat content and decreased post-milking free FA concentration. Numerous interactions (significant but of limited quantitative extent) between the CSN1S1 genotype and EL feeding were shown on milk composition, including 26 FA proportions or delta-9 desaturation ratios, and post-milking free FA concentration.

Effects of diet on casein and fatty acid profiles of milk from goats differing in genotype for αS1-casein synthesis

This study investigated the interactions between nutrition and the genotype at αS1-CN loci (CSN1S1) in goats, evaluating the impact of fresh forage-based diets and an energy supplement on the casein and fatty acid (FA) profiles of milk from Girgentana goats. Twelve goats were selected for having the same genotype at the αS2-CN, β-CN, and κ-CN loci and differing in the CSN1S1 genotype: homozygous for strong alleles (AA) or heterozygous for strong and weak alleles (AF). Goats of each genotype were divided into three groups and, according to a 3 × 3 Latin square design, fed ad libitum three diets: sulla fresh forage (SFF), SFF plus 800 g/day of barley (SFB), and mixed hay plus 800 g/day of barley (MHB). The SFB diet led to higher-energy intake and milk yield. The energy-supplemented diets (SFB, MHB) reduced milk fat and urea and increased coagulation time. The fresh forage diets (SFF, SFB) increased dry matter (DM) and crude protein (CP) intake and milk β-CN. Diet had a more pronounced effect than CSN1S1 genotype on milk FA profile, which was healthier from goats fed the SFF diet, due to the higher content of rumenic acid, polyunsaturated, and omega-3 FAs. The AA milk had longer coagulation time and higher curd firmness, higher short- and medium-chain FAs (SMFA), and lower oleic acid than AF milk. Significant diet by genotype interactions indicated the higher milk yield of AA goats than AF goats with the higher-energy SFB diet and the lower synthesis of SMFA in AF than in AA goats with the SFF diet.

Influence of fresh forage-based diets and αS1-casein (CSN1S1) genotype on nutrient intake and productive, metabolic, and hormonal responses in milking goats

Polymorphism at the αS1-casein locus (CSN1S1) in goats influences several milk production traits. Milk from goats carrying strong alleles, which are associated with high αS1-casein (αS1-CN) synthesis, has higher fat and casein contents, longer coagulation time and higher curd firmness than milk from goats with weak alleles linked to low αS1-CN content. Nutrition also affects these milk properties; therefore, it is important to better understand the interaction between dietary characteristics and the CSN1S1 genotype in goats. This study aimed to investigate the effect of fresh forage based diet or energy supplement on feeding behavior, milk production, and metabolic and hormonal parameters of Girgentana goats with different genotypes at CSN1S1 loci. From a group of goats genotyped by PCR at the DNA level, 12 were selected because they had the same genotype for αS2-CN, β-CN, and κ-CN but a different genotype for αS1-CN: 6 were homozygous for strong alleles at the CSN1S1 loci (AA) and 6 were heterozygous for a weak allele (AF). Goats of each genotype were allocated to 3 subgroups and fed 3 diets ad libitum in a 3×3 Latin square design. The diets were sulla (Hedysarum coronarium L.) fresh forage, sulla fresh forage plus 800g/d of barley meal (SFB), and mixed hay plus 800g/d of barley meal (MHB). Diet had a stronger effect than CSN1S1 genotype. The SFB diet led to the highest energy intake, dry matter (DM) digestibility, and milk yield. The fresh forage diets (SFF and SFB) increased DM and crude protein (CP) intake, CP digestibility, and milk CN compared with the MHB diet. The diets supplemented with energy (SFB, MHB) reduced milk fat and urea, improved CP utilization for casein synthesis, and limited body fat mobilization, in accordance with a lower level of nonesterified fatty acids and higher levels of glucose and IGF-1. With regard to CSN1S1 genotype, AA goats showed higher CP digestibility and lower free thyroxine hormone and cholesterol levels than AF goats. Significant diet × genotype interactions indicated how AA goats, compared with AF goats, showed higher DM digestibility and milk yield when fed the SFB diet, which had more energy. A reduction in free triiodothyronine hormone occurred in AF goats fed the MHB diet, whereas no differences were observed in AA goats. These results demonstrate how goats with a higher capacity for αS1-CN synthesis exhibit more efficient energy and protein utilization, evident at the digestive level, and better productive responses to high-nutrition diets.

Genetic polymorphism at the CSN1S1 gene in Girgentana dairy goat breed

The aim of this work was to evaluate the variability of the αs1-casein locus in the endangered Girgentana dairy goat breed in order to define genetic improvement and a conservation program for this breed. The study was performed on 200 dairy goats by means of different PCR protocols. The most frequent alleles were A (0.590) and F (0.290) followed by B (0.065) and N (0.047). CSN1S1 E allele was identified with a very low frequency (0.008). The most common genotype was AF (0.365) followed by AA (0.340). The high frequency of the strong genotypes is associated with the production of milk with high fat and protein content and with optimal technological properties. In Girgentana goat breed, the CSN1S1 genotype information could be utilised in selection strategies for milk protein content and milk yield, in order to select genetic lines for the production of ‘drinking milk’ using weak and null genotypes, and for niche products using strong genotypes.

Impact of Sow Milk Protein Polymorphism on Piglet Rearing

Impact of Sow Milk Protein Polymorphism on Piglet RearingThe aim of the investigations was to ascertain interrelationships between polymorphic fractions of milk proteins and rearing results of piglets from Złotnicka White sows. The experimental material comprised 20 sows of the native Złotnicka White breed. Pigs of this breed are included in the National Genetic Resources Conservation Programme. Investigations included two successive (2nd and 3rd) lactations of sows during which the following parameters were determined: number and weight of piglets on days 1, 7, 14, 21 and 28; weight gains of individual piglets during the period from day 1 to 7, from day 8 to 14, from day 15 to 21 and from day 22 to 28; as well as mortality for the entire period of rearing, i.e. from day 1 to day 28 of age. A total of 425 piglets born in 40 litters (20 sows x 2 lactations) were investigated. As a result of electrophoretic separations, the following four protein fractions were isolated from sow milk: αs1-casein (CSN1S1), genotypes AA, AB, BB and BC; β-casein (CSN2), genotypes AA, AB and BB; κ-casein (CSN3), genotypes AA, AB and BB; β-lactoglobulin (LGB), genotypes AA and BB. The present study showed that milk from sows of AA CSN1S1 and AA LGB genotypes appeared to be more valuable and nourishing, as indicated by the fact that these sows reared piglets which were characterized by the best production results, i.e. body weight, weight gains and the lowest percentage mortality. The least dynamic results were obtained by piglets originating from litters of sows of the AA-CSN3 genotype.

Effect of diet at different energy levels on milk casein composition of Girgentana goats differing in CSN1S1 genotype

Eighteen Girgentana lactating goats, nine homozygous for strong alleles (AA) and nine homozygous for weak alleles (FF) at αs1-casein (CSN1S1) locus, were used to evaluate the effect of genotype, diet and genotype×diet (G×D) interaction on the composition of goat milk caseins. Goats were used in a 2×2 factorial arrangement of treatments, with two genotypes (AA, FF) and two diets at different energy levels (high-energy diet (D65) and low-energy diet (D100)). The experiment consisted of two simultaneous 2×2 Latin squares for the two genotypes, with one square for each level of energy. Capillary electrophoresis was used for the determination of relative casein (CN) composition. αs1-CN, κ-CN and β-CN yield was significantly higher with D65 than D100 (10.2 vs 7.2; 3.8 vs 2.6; 18.6 vs 13.6g/d, respectively). Genotype significantly affected (P<0.05) αs2-CN and αs1-CN yield: αs1-CN was higher in AA than FF goat milk (15.5 vs 2.4g/d), while αs2-CN was higher in FF than AA goat milk (4.7 vs 2.8g/d); no genotype effect (P>0.05) was reported for κ-CN and β-CN yield. As concerning individual casein concentration, αs1-CN was higher for AA than FF goat (12.4 vs 1.5g/kg milk), whereas αs2-CN and β-CN were higher in FF than AA milk (4.3 vs 1.4; 15.6 vs 12.9g/kg, respectively); also κ-CN tended to be higher in FF goats. Diet did not significantly influence concentration of individual caseins. A significant G×D interaction was found only for αs1-CN concentration, which decreased (−10%) when AA goats shifted from D100 to D65. In conclusion, high energy input consistently improved total casein yield beside genotype. The higher casein yield of AA goats mainly depends on αs1-CN biosynthesis; moreover, the lower presence of αs1-CN in FF goat milk may be partially counterbalanced by the other caseins.

Goat milk allergenicity as a function of αS1-casein genetic polymorphism

Cow milk allergy is the most frequent allergy in the first years of life. Milk from other mammalian species has been suggested as a possible nutritional alternative to cow milk, but in several cases, the clinical studies showed a high risk of cross-reactivity with cow milk. In the goat species, αS1-casein (αS1-CN), coded by the CSN1S1 gene, is characterized by extensive qualitative and quantitative polymorphisms. Some alleles are associated with null (i.e., CSN1S1*01) or reduced (i.e., CSN1S1*F) expression of the specific protein. The aim of this work was to obtain new information on goat milk and to evaluate its suitability for allergic subjects, depending on the genetic variation at αs1-CN. Individual milk samples from 25 goats with different CSN1S1 genotypes were analyzed by sodium dodecyl sulfate PAGE and immunoblotting, using monoclonal antibodies specific for bovine α-CN and sera from children allergic to cow milk. A lower reaction was observed to 2 goat milk samples characterized by the CSN1S1* 0101 and 01F genotypes. Moreover, a fresh food skin prick test, carried out on 6 allergic children, showed the lack of positive reaction to the 0101 milk sample and only one weak reactivity to the 01F sample. The risk of cross-reactivity between cow and goat milk proteins suggests the need for caution before using goat milk for infant formulas. However, we hypothesize that it can be used successfully in the preparation of modified formulas for selected groups of allergic patients. The importance of taking the individual goat CN genetic variation into account in further experimental studies is evident from the results of the present work.