269 research outputs found
Estimated requirements of net energy, digestible protein and NDF intake of young Chianina bulls from 400 kg liveweight to slaughter
Three equations have been elaborated and proposed to predict the requirements of net energy and protein digestible in the intestine and NDF voluntary intake of growing young Chianina bulls, starting from 400 kg live weight. The animals examined in the present study were 100 young Chianina bulls starting from about 400 kg live weight, at 10 months of age, up to the average slaughter weight of 800 kg at 20 months average age. The diet was based on hay and concentrates. The equation for the prediction of net energy fits quite perfectly to another experimental equation formerly proposed by Giorgetti and is characterised by a very high value of the correlation coefficient for the regression comparison between observed and predicted figures (R2=0.90). The statistical reliance degree of the PDIN prediction equation is lower, but still very good (R2=0.75 between observed and predicted values), but that of the estimate of NDF daily intake resulted very poor (R2=0.26 between observed and predicted values), probably due to the non homogeneity of the intake capacity of the 100 examined animals. The correlation between daily gains and the concentration of NDF in the diet DM results good (R2=0.87), showing that young Chianina bulls take advantage of the diet fibre. Further useful indications on the nutritional and dietary requirements of young Chianina bulls are added to the scarce information currently available
Use of a citrus by-product in broilers diets
The European Union is about to ban antibiotics as growth promoters in animal feeds. Organic products have been recently revalued and the animal science research showed a great interest in the study of alternative natural nutraceutical products in animal feeding. Flavonoids are plant pigments able to inhibit or kill many bacterial strains, to destroy some pathogenic protozoa and to scavenge free radicals
Effect of forage /concentrate ratio and soybean oil supplementation on in vitro fatty acid profile of sheep rumen liquor.
In an in vitro trial, the effect of forage/concentrate ratio (F/C) and soybean oil (SO) supplementation on rumen liquor fatty acids profile was studied with the aim to evaluate changes in the profiles of biohydrogenation intermediates during the fermentation process. Feed samples of four diets were inoculated with sheep rumen liquor: i) high F/C and no SO; ii) high F/C and SO; iii) low F/C and no SO; iv) low F/C and SO. Fermentation times were 6, 12 h. Trans fatty acid were formed when oil supplement or a low forage content were present in the diets, but at different times of fermentation, as a consequence of a shift from the usual rumen biohydrogenation pathway. In fact, when a higher forage percentage was included in the diet, the alternative pathways of rumen biohydrogenation did not occur; trans10 C18:1 concentration was low and neither trans10, cis12 CLA nor trans, trans CLA appeared
Effect of oleic and conjigated linoleic acid in diet of broiler chickens on the live growth performances, carcass traits and meat fatty acid profile
Olive oil and CLA enriched olive oil were compared with each other in a growth trial with broiler chickens,
as energy supplements to the diet. A commercial CLA blend was used at the level of 1 kg per 100 kg
mixed integrated feed.
Two hundred and forty commercial hybrid broilers (Ross 308) were randomly subdivided and allotted to
8 pens of 30 birds each. Four pens of birds were fed the olive oil diet and considered the control group;
the other 4 pens were fed the olive oil supplemented with CLA and considered the treated group. The
experiment lasted 47 days.
The live performance of the treated birds resulted different from the performance of the control ones: the
final body weight was slightly lighter (2.544 kg vs 2.639 kg; P≤0.05) with a lower feed intake (4.886 kg feed
vs 4.998 kg, P≤0.05) and, of course, an almost perfectly overlapping feed/gain ratio (1.90 vs 1.91).
The fatty acid composition of the breast fat of the CLA treated birds resulted enriched by the two major
CLA isomers, trans 10 cis 12 and cis 9 trans 11, whereas oleic acid and the linoleic, linolenic and arachidonic
polyunsaturated acids showed a decrease (P≤0.05).
CLA appears a recommendable ingredient in the diets of broilers as it improves the beneficial characteristics
of poultry meat
Polyphenols and organic acids as alternatives to antimicrobials in poultry rearing: a review.
For decades antibiotics have been used in poultry rearing to support high levels of production. Nevertheless, several problems have arisen because of the misuse of antibiotics (i.e., antibiotic resistance, residues in animal products, environmental pollution). Thus, the European Union (EU) as well as the European Food Safety Authority (EFSA) promote action plans to diminish the use of antibiotics in animal production. Alternatives to antibiotics have been studied. Polyphenols (PPs) or organic acids (OAs) seem to be two accredited solutions. Phenolic compounds, such as phenols, flavonoids, and tannins exert their antimicrobial effect with specific mechanisms. In contrast, short chain fatty acids (SCFAs) and medium chain fatty acids (MCFAs), the OAs mainly used as antibiotics alternative, act on the pathogens depending on the pKa value. This review aims to collect the literature reporting the effects of these substances applied as antimicrobial molecules or growth promoter in poultry feeding (both for broilers and laying hens). Organic acids and PPs can be used individually or in blends, exploiting the properties of each component. Collected data highlighted that further research needs to focus on OAs in laying hens’ feeding and also determine the right combination in blends with PPs
Mixtures of mono-, di- and tri-glycerides as energy supplements to broilers' diets
Mixtures of mono-, di- and tri-glycerides from olive oil (MDT) were added to: palm oil (PO), olive oil (OO), soybean oil (SO), free fatty acids from palm oil (PFA), free fatty acids from olive oil (OFA). The compound mixtures were used as energy supplements in the diets of broiler chickens in comparison with plain SO and plain animal fat (AF). Two hundred and ten birds were randomly allotted to 7 dietary treatments with the diverse oil sources: 6 birds per cage, 5 cages per treatment. The effects of the treatments on growth rates, feed/gain ratios and acidic composition of abdominal fat of hybrid Ross 308 female chickens were studied. The animals were slaughtered at the end of the trial, at day 35. The breast meat quality was then evaluated by a panel of 15 trained members and analysed for shelf life duration. The AF treat- ment gave the highest weight gain, but only in the first week. MDT + OO (50/50) resulted the best combination, with slight, non significant, better performances and a decidedly better quality in terms of acidic composition of abdominal fat, taste and juiciness of breast meat and shelf life
Mixture of mono- di- and tri-glycerides as energy supplements to broilers diets.
Mixtures of mono-, di- and tri-glycerides from olive oil (MDT) were added to: palm oil (PO), olive oil (OO), soybean oil
(SO), free fatty acids from palm oil (PFA), free fatty acids from olive oil (OFA). The compound mixtures were used as
energy supplements in the diets of broiler chickens in comparison with plain SO and plain animal fat (AF). Two hundred
and ten birds were randomly allotted to 7 dietary treatments with the diverse oil sources: 6 birds per cage, 5 cages per
treatment. The effects of the treatments on growth rates, feed/gain ratios and acidic composition of abdominal fat of
hybrid Ross 308 female chickens were studied. The animals were slaughtered at the end of the trial, at day 35. The breast
meat quality was then evaluated by a panel of 15 trained members and analysed for shelf life duration. The AF treatment
gave the highest weight gain, but only in the first week. MDT + OO (50/50) resulted the best combination, with
slight, non significant, better performances and a decidedly better quality in terms of acidic composition of abdominal
fat, taste and juiciness of breast meat and shelf lif
Transfer of dietary fatty acids from butyric acid fortified canola oil into the meat of broilers
The literature reported positive beneficial effects of butyric acid and canola oil on
production performance traits of broiler chickens. Three hundred hybrid Ross 708 (150 males and 150
females) were randomly allotted to 10 pens per treatment with 5 males and 5 females per pen. Ten
pens were administered a diet supplemented with soybean oil (control), ten pens the same basal diet
but supplemented with a blend of mono-, di-, tri-glyceride of butyric acid added to soybean oil (T1) and
ten pens the same basal diet supplemented with a mix of soybean and canola oil containing butyrate
(T2). No differences in final body weight, dressing percentage, liver and thigh weight were found between
groups. The T2 birds showed the highest feed/gain ratio (P<0.05). The control group showed the
highest value for breast weight while the highest quantity of abdominal fat was in T2 carcasses. Fatty
acid profile was significantly influenced by the presence of oil supplements, not only quantitatively but
also qualitatively
Monobutirryne: a novel feed additive in the diet of broiler chickens.
Purpose of the present work was to validate the monoglyceride of butyric acid (MB) as an alternative to antibiotics as growth promoters in the diet of broiler chickens. The approach is a kind of prolongation of previous works, in which a blend of mono-, di- and tri-glycerides of butyric acid have been previously tested. The results indicated that MB was very efficient in limiting the mortality of birds challenged with Eimeria spp., but did not appreciably impair the performance of unchallenged birds. In conclusion, the metabolisable energy content of MB appeared comparable with that of soybean oil and MB a reliable coccidiostat
Study of 13CR-4NI-(MO) (F6NM) steel grade heat treatment for maximum hardness control in industrial heats
The standard NACE MR0175 (ISO 15156) requires a maximum hardness value of 23 HRC for 13Cr-4Ni-(Mo) steel grade for sour service, requiring a double tempering heat treatment at temperature in the range 648–691°C for the first tempering and 593–621°C for the second tempering. Difficulties in limiting alloy hardness after the tempering of forged mechanical components (F6NM) are often faced. Variables affecting the thermal behavior of 13Cr-4Ni-(Mo) during single and double tempering treatments have been studied by means of transmission electron microscopy (TEM) observations, X-ray diffraction measurements, dilatometry, and thermo-mechanical simulations. It has been found that relatively low Ac1 temperatures in this alloy induce the formation of austenite phase above 600°C during tempering, and that the formed, reverted austenite tends to be unstable upon cooling, thus contributing to the increase of final hardness via transformation to virgin martensite. Therefore, it is necessary to increase the Ac1 temperature as much as possible to allow the tempering of martensite at the temperature range required by NACE without the detrimental formation of virgin martensite upon final cooling. Attempts to do so have been carried out by reducing both carbon (<0.02% C) and nitrogen (<100 ppm) levels. Results obtained herein show final hardness below NACE limits without an unacceptable loss of mechanical strength
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