A. Caroli

Invited review: Milk protein polymorphisms in cattle: Effect on animal breeding and human nutrition

The 6 main milk proteins in cattle are encoded by highly polymorphic genes characterized by several nonsynonymous and synonymous mutations, with up to 47 protein variants identified. Such an extensive variation was used for linkage analysis with the description of the casein cluster more than 30 yr ago and has been applied to animal breeding for several years. Casein haplotype effects on productive traits have been investigated considering information on the whole casein complex. Moreover, mutations within the noncoding sequences have been shown to affect the specific protein expression and, as a consequence, milk composition and cheesemaking. Milk protein variants are also a useful tool for breed characterization, diversity, and phylogenetic studies. In addition, they are involved in various aspects of human nutrition. First, the occurrence of alleles associated with a reduced content of different caseins might be exploited for the production of milk with particular nutritional qualities; that is, hypoallergenic milk. On the other hand, the frequency of these alleles can be decreased by selection of sires using simple DNA tests, thereby increasing the casein content in milk used for cheesemaking. Furthermore, the biological activity of peptides released from milk protein digestion can be affected by amino acid exchanges or deletions resulting from gene mutations. Finally, the gene-culture coevolution between cattle milk protein genes and human lactase genes, which has been recently highlighted, is impressive proof of the nonrandom occurrence of milk protein genetic variation over the centuries.

High Polymorphism in the K-Casein (CSN3) Gene from Wild and Domestic Caprine Species Revealed by DNA Sequencing

We assessed polymorphisms in exon IV of the kappa-casein gene (CSN3) in ten different breeds of domestic goat (Capra hircus) from three continents and in three related wild caprine taxa (Capra ibex, Capra sibirica and Capra aegagrus). Thirty-five DNA samples were sequenced within a 558 bp fragment of exon IV. Nine polymorphic sites were identified in domestic goat, including four new polymorphisms. In addition to four previously described polymorphic positions, a total of 13 polymorphisms allowed the identification of 13 DNA variants, corresponding to 10 protein variants. Because of conflicting nomenclature of these variants, we propose a standardized allele designation. CSN3*A, CSN3*B, and CSN3*D were found as widely distributed alleles in European goat breeds. Within Capra ibex we identified three variants and showed that the sequence of Capra aegagrus is identical to the most common Capra hircus variant, consistent with Capra aegagrus being the wild progenitor of domestic goats. A dendrogram was drawn to represent the molecular network between the caprine CSN3 variants.

Detection of the new emerging rabbit haemorrhagic disease type 2 virus (RHDV2) in Sicily from rabbit (Oryctolagus cuniculus) and Italian hare (Lepus corsicanus).

Rabbit haemorrhagic disease virus (RHDV), a member of the genus Lagovirus, causes rabbit haemorrhagic disease (RHD), a fatal hepatitis of rabbits, not previously reported in hares. Recently, a new RHDV-related virus emerged, called RHDV2. This lagovirus can cause RHD in rabbits and disease and mortality in Lepus capensis (Cape hare). Here we describe a case of RHDV2 infection in another hare species, Lepus corsicanus, during a concurrent RHD outbreak in a group of wild rabbits. The same RHDV2 strain infected rabbits and a hare, also causing a RHD-like syndrome in the latter. Our findings confirmed the capability of RHDV2 to infect hosts other than rabbits and improve the knowledge about the epidemiology and the host range of this new lagovirus.

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 0(1)) 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 0(1)0(1) and 0(1)F genotypes. Moreover, a fresh food skin prick test, carried out on 6 allergic children, showed the lack of positive reaction to the 0(1)0(1) milk sample and only one weak reactivity to the 0(1)F 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.

Short communication: Milk protein genetic variation and casein haplotype structure in the Original Pinzgauer cattle

Milk protein genetic polymorphisms are often used for characterizing domesticated mammalian species and breeds, and for studying associations with economic traits. The aim of this work was to analyze milk protein genetic variation in the Original Pinzgauer, a dual-purpose (dairy and beef) cattle breed of European origin that was influenced in the past by human movements from different regions as well as by crossbreeding with Red Holstein. A total of 485 milk samples from Original Pinzgauer from Austria (n=275) and Germany (n=210) were typed at milk proteins alpha(S1)-casein, beta-casein, kappa-casein, alpha-lactalbumin, and beta-lactoglobulin by isoelectrofocusing to analyze the genetic variation affecting the protein amino acid charge. The Original Pinzgauer breed is characterized by a rather high genetic variation affecting the amino acid charge of milk proteins, with a total of 15 alleles, 12 of which were found at a frequency >0.05. The most polymorphic protein was beta-casein with 4 alleles detected. The prevalent alleles were CSN1S1*B, CSN2*A(2), CSN1S2*A, CSN3*A, LGB*A, and LAA*B. A relatively high frequency of CSN1S2*B (0.202 in the whole data set) was found, mainly occurring within the C-A(2)-B-A haplotype (in the order CSN1S1-CSN2-CSN1S2-CSN3), which seems to be peculiar to the Original Pinzgauer, possibly because the survival of an ancestral haplotype or the introgression of Bos indicus.

Short Communication: The β-Casein (CSN2) Silent Allele C1 Is Highly Spread in Goat Breeds

Several single nucleotide polymorphisms have been identified in the goat milk casein genes, most of them modifying the amino acid sequence of the coded protein. At least 9 variants have been found in goat beta-CN (CSN2); 6 of them were characterized at the DNA level (A, A1, C, E, 0, and 0), whereas the other 3 variants were described only at the protein level. The recently identified silent A1 allele is characterized by a C-->T transition at the 180th nucleotide of the ninth exon. In the present work, typing results from different breeds (3 Italian, 3 German, and a composite of African breeds for a total of 335 samples) demonstrated that the same mutation is carried by the CSN2*C allele. In addition, the T nucleotide at the 180th nucleotide of the ninth exon was always associated with CSN2*C in all the breeds analyzed. Thus, another silent allele occurs at goat CSN2 and can be named CSN2*C1. The much wider distribution of C1 with respect to the A1 allele indicates that the single nucleotide polymorphisms characterizing the silent mutation originated from CSN2*C. A method for the identification of this allele simultaneously with 5 of the 6 DNA-characterized alleles is also proposed. The mutation involved codifies for the same protein of the C allele; nevertheless, its location in the 3 untranslated region of the gene might affect the specific casein expression.

Psittacine Beak and Feather Disease–like Illness in Gouldian Finches (Chloebia gouldiae)

SUMMARY Beak and feather disease virus (BFDV) is a member of the genus Circovirus and causes psittacine beak and feather disease (PBFD) in Psittaciformes. PBFD is a severe disease generally characterized by immunodeficiency and beak and feather disorders. Although Circovirus spp. have been detected in several nonpsittacine species, little is known about the symptoms and the disease associated with this infection in birds other than Psittaciformes. In this study, we report the identification of Circovirus infection in a flock of Gouldian finches showing beak and feather disorders. Sequence analyses on the rep gene of the virus highlighted a strong similarity at nucleotide and amino acid levels with the corresponding regions of BFDV from psittacine species. By contrast, it was more distant to circoviruses identified in finch and canary. RESUMEN Reporte de Caso—Problema similar a la enfermedad del pico y las plumas (PBFD) de los psitácidos en diamantes de Gould (Chloebia gouldiae). El virus de la enfermedad del pico y de las plumas (BFDV) es un miembro del género Circovirus y causa la enfermedad del mismo nombre (con las siglas en inglés PBFD) en psitácidos. La enfermedad del pico y las plumas es una enfermedad grave caracterizada generalmente por inmunodeficiencia y trastornos del pico y las plumas. Aunque se han detectado Circovirus spp. en varias especies no psitácidas, poco se sabe acerca de los signos y enfermedad asociadas con esta infección en las aves distintas a las Psittaciformes. En este estudio, se presenta la identificación de la infección por circovirus en una parvada de pinzones de Gould que mostraron trastornos de pico y plumas. El análisis de la secuencia del gene rep del virus mostró una gran similitud a nivel de nucleótidos y de aminoácidos con las regiones correspondientes al virus de la enfermedad del pico y plumas de las especies de psitácidos. Por el contrario, este virus fue más distante al circovirus identificado en el pinzón y en el canario.

Technical Note: Simultaneous Identification of CSN1S2 A, B, C, and E Alleles in Goats by Polymerase Chain Reaction-Single Strand Conformation Polymorphism

Most variability in goat caseins originates from the high number of genetic polymorphisms often affecting the specific protein expression, with strong effects on milk composition traits and technological properties. At least 7 alleles have been found in the goat alpha(S2)-CN gene (CSN1S2). Five of them (CSN1S2*A, CSN1S2*B, CSN1S2*C, CSN1S2*E, and CSN1S2*F) are widespread in most breeds, whereas the other 2 (CSN1S2*D and CSN1S2*0) are rarer alleles. Four different PCR-RFLP tests are needed to detect all of these variants at the DNA level. The objective of this study was to develop and validate a rapid method for typing 4 of the 5 most-common goat CSN1S2 alleles by means of PCR-single strand conformation polymorphism (SSCP). The method was validated by analyzing 37 goat samples at the protein and DNA level, respectively, by milk isoelectrofocusing and PCR-RFLP methods already described. The genotypes obtained using the PCR-SSCP approach were in full agreement with those obtained by the validation analyses. The newly developed PCR-SSCP approach provides an accurate and inexpensive assay highly suitable for genotyping goat CSN1S2.

Genetic study of Murgese horse from genealogical data and microsatellites

Abstract The black or rarely roan Murgese is a mesomorph horse, mainly reared in Apulia, recently selected for the saddle. The first official registry of Murgese was established in 1926. All the existing Murgese horses can be traced back to a small number of founders (46 founder mares and 9 stallions). This work aims to monitor the genetic structure of the actual population by analysing the available genealogical information from 2708 animals and a data-set containing 563 typing records of twelve microsatellites. Inbreeding coefficients were estimated for the whole sample and for the animals born from 1992 to 1999. A total of 23 generations were found. The average inbreeding coefficient was 0.0165 for the last three generations, whereas inbreeding was below 2% in animals born in the 92-99 period. The contribution of founders was unbalanced. The overall Fis coefficient estimation was 0.025 and suggests that mating is generally at random in the population. However, some statistics obtained from this study, i.e. the inbreeding coefficient higher than 0.015 in the 70 animals of the 19th, 20th, and 21st generations, should induce breeders to more attention in planning mating.

Environmental contamination by Aspergillus spp. in laying hen farms and associated health risks for farm workers

Data on the occurrence and epidemiology of Aspergillus spp. in laying hens farms are scant. With the aims of determining levels of airborne contamination in laying hen farms and evaluating the potential risk of infection for workers and animals, 57 air samples from 19 sheds (Group I), 69 from faeces (Group II), 19 from poultry feedstuffs (Group III) and 60 from three anatomical sites (i.e. nostrils, pharynx, ears) of 20 farm workers (Group IV) were cultured. The Aspergillus spp. prevalence in samples ranged from 31.6% (Group III) to 55.5% (Group IV), whereas the highest conidia concentration was retrieved in Group II (1.2 × 10(4) c.f.u. g(-1)) and in Group III (1.9 × 10(3) c.f.u. g(-1)). The mean concentration of airborne Aspergillus spp. conidia was 70 c.f.u. m(-3) with Aspergillus fumigatus (27.3%) being the most frequently detected species, followed by Aspergillus flavus (6.3%). These Aspergillus spp. were also isolated from human nostrils (40%) and ears (35%) (P<0.05) (Group IV). No clinical aspergillosis was diagnosed in hens. The results demonstrate a relationship between the environmental contamination in hen farms and presence of Aspergillus spp. on animals and humans. Even if the concentration of airborne Aspergillus spp. conidia (i.e. 70 c.f.u. m(-3)) herein detected does not trigger clinical disease in hens, it causes human colonization. Correct management of hen farms is necessary to control environmental contamination by Aspergillus spp., and could lead to a significant reduction of animal and human colonization.