Gabriele Tornambè

Persistence of wild Streptococcus thermophilus strains on wooden vat and during the manufacture of a traditional Caciocavallo type cheese

The present work was undertaken to evaluate the influence of the wooden dairy plant equipment on the microbiological characteristics of curd to be transformed into Caciocavallo Palermitano cheese. Traditional raw milk productions were performed concomitantly with standard cheese making trials carried out in stainless steel vat inoculated with a commercial starter. Milk from two different farms (A and B) was separately processed. The wooden vat was found to be a reservoir of lactic acid bacteria (LAB), while unwanted (spoilage and/or pathogenic) microorganisms were not hosted or were present at very low levels. All microbial groups were numerically different in bulk milks, showing higher levels for the farm B. LAB, especially thermophilic cocci, dominated the whole cheese making process of all productions. Undesired microorganisms decreased in number or disappeared during transformation, particularly after curd stretching. LAB were isolated from the wooden vat surface and from all dairy samples, subjected to phenotypic and genetic characterization and identification. Streptococcus thermophilus was the species found at the highest concentration in all samples analyzed and it also dominated the microbial community of the wooden vat. Fourteen other LAB species belonging to six genera (Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Streptococcus and Weissella) were also detected. All S. thermophilus isolates were genetically differentiated and a consortium of four strains persisted during the whole traditional production process. As confirmed by pH and the total acidity after the acidification step, indigenous S. thermophilus strains acted as a mixed starter culture.

Intake and milk production of goats grazing Sulla forage under different stocking rates

Abstract A total of 24 Girgentana goats was divided into 3 homogeneous groups grazing a sulla monoculture under stocking rate of 30, 50 or 70 goats/ha (LSR, MSR and HSR). Available biomass, herbage selected by goats and milk yield were measured and sampled. The DM intake of goats and its botanic composition and digestibility were assessed by the n-alkane method. Grazing at HSR was suspended 18 d before MSR and LSR (35 vs. 53 d), due to the low biomass availability. Over the first 35 d of grazing, the HSR reduced height and availability of herbage. The herbage intake and milk yield of goats increased from HSR to LSR, without relevant changes in milk quality. During all grazing period (53 d), the higher grazing pressure led to a lower total milk yield per goat, whereas the HSR produced the highest daily and total milk amount per ha.

Relationships between dietary factors and milk urea nitrogen level in goats grazing herbaceous pasture

Abstract This investigation aimed to individuate the dietary factors affecting the milk urea nitrogen (MUN) concentration in goats grazing herbaceous pasture and, particularly, to verify the relationship linking the diet crude protein (CP) content to MUN. A total of 205 individual observations regarding dietary and milk variables of 37 Girgentana goats involved in two experiments were used. Goats, averaging 154±14 days in milk and 38.1±5.4 kg of live weight, grazed on swards and received 500 g/d of barley meal. Sward biomass, herbage selected by goats and individual milk yield were measured and sampled weekly. The herbage intake and diet digestibility were estimated by the n-alkane method. Milk urea content was determined by an enzymatic method and transformed in MUN (MUN=urea*0.4665). The MUN concentration (9.7-35.4 mg/dl) was positively correlated with diet CP content (13.7-26.0% of dry matter (DM); r=0.76; P<0.001), pasture allowance (39-151 kg DM/goat; r=0.42; P<0.001), diet net energy for lactation concentration (NEl) (1.5-1.9 Mcal/kg DM; r=0.37; P<0.001) and milk yield (320-2250 g/d; r=0.25; P<0.001), and negatively related with NDF (18.7-37.4% DM; r=-0.69; P<0.001) and diet digestibility (72.6-92.5%; r=-0.33; P< 0.001). The stepwise selection from dietary variables and milk yield showed dietary CP percentage to be the single variable explaining the most variation in MUN (R2=0.56; P< 0.0001). The other variables entering into the model were diet NDF, 3.5% fat-corrected milk (FCM), DM intake and NDF intake (total R2=0.66). Including the CP/NEl and CP/NDF ratios of diet in the stepwise regression model, the CP/NDF ratio alone explained 60.1% of MUN variability, followed by barley proportion in the diet, FCM and diet CP concentration, absorbing an extra 4.6% of MUN variability. A linear regression, fitting mean feeding treatment per time data of MUN and dietary CP concentration (n=28)[CP(% of DM)=6.91±1.42+0.61±0.06*MUN (mg/dl); R²=0.79; P<0.0001], suggests that MUN could be used for predicting the CP content of the diet, as a tool for developing feeding strategies aimed at balancing the rations of grazing goats through adequate supplementation. Further data from experiments on grazing goats in different environmental conditions are required in order to define a more robust relationship by which to predict the dietary CP content by MUN.

Effects of feeding green forage of sulla (Hedysarum coronarium L.) on lamb growth and carcass and meat quality

The nutritional effects of sulla (Hedysarum coronarium L.) forage containing condensed tannins (CT) on growth of lambs, and carcass and meat quality were investigated. Thirty-two male Comisana lambs aged 100 ± 8 days weighing 19.0 ± 2.8 kg were fed fresh forage of sulla or CT-free annual ryegrass (Lolium multiflorum Lam. subsp. Wersterwoldicum) for 49 days until slaughter; in addition, each lamb was supplied with 200 g/days of concentrate. Eight lambs per diet had been previously treated with anthelmintic drugs to remove nematode parasites. Measurements of BW and feed intake, and counts of faecal nematode eggs were made. Carcass parameters were recorded after slaughter, and tissue components of the hind leg were determined. Longissimus dorsi meat was evaluated for pH, colour, thawing and cooking losses, Warner-Bratzler shear force, chemical composition and sensory properties based on triangle tests. Relative to ryegrass-fed lambs, sulla-fed lambs had significantly greater dry matter (DM) and protein intake, a more favourable feed conversion ratio, and superior growth rate, final BW at 150 days of age, carcass weight, yield and fatness. These results were attributed to the high protein and non-structural carbohydrate content of sulla, and also to the moderate CT content of sulla (16.7 and 20.3 g/kg of DM in offered and consumed sulla forage, respectively). Anthelmintic treatment did not affect lamb growth, as the level of parasitic infection (initial and final) was low. The physical, chemical and sensory properties of the lamb meat were not influenced by 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 800 g/d of barley meal (SFB), and mixed hay plus 800 g/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.

Effect of production systems on sensory characteristics of PDO Cantal cheese

Riassunto Effetto dei sistemi di produzione sulle caratteristiche sensoriali di formaggi Cantal DOP. Scopo del lavoro è verificare se il latte proveniente da allevamenti caratterizzati da condizioni di produzione differenti, comporti l’ottenimento di formaggi con caratteristiche sensoriali diverse. Nell’inverno 2003, nel corso di 2 settimane, 22 formaggi Cantal sono stati realizzati in condizioni sperimentali a partire dal latte di 11 aziende differenti per sistema di produzione. I formaggi, a 3 mesi di stagionatura, sono stati oggetto di analisi chimica, reologica e sensoriale. Un doppio approccio é stato utilizzato nell’elaborazione statistica: l’individuazione di formaggi con caratteristiche similari e la valutazione dell’effetto della razione sulle caratteristiche dei formaggi. I formaggi ottenuti da una razione costituita per il 100% da fieno si sono caratterizzati per un gusto più deciso ed una consistenza più cremosa. I risultati ottenuti confermano come la variabilità delle caratteristiche sensoriali del formaggio é legata ai differenti sistemi di gestione delle aziende e soprattutto alle differenti razioni di base.

Utilization of mulberry leaves (Morus latifolia cv. Kokusou 21) in diets for dairy ewes

Abstract Twelve Valle del Belice lactating ewes were divided into three homogeneous groups and fed ad libitum the following diets in a 3x3 Latin square design: sulla hay (HA); sulla hay and Mulberry leaves (M. leaves) (HM); M. leaves (MU). DM intake of MU ewes was lower than that of HM ewes, with an intermediate level for HA ewes. HM ewes showed to prefer M. leaves to hay, but their need to balance the high protein and low NDF contents of M. leaves by eating hay also emerged. Milk yield increased as the dietary content of M. leaves increased In addition, the use of HM and MU diets led to higher milk fat and urea content in comparison with the HA diet. The results confirmed that M. leaves are a suitable fresh feeding source for sheep, and suggested to use them in association with fibre-rich feeds.