Response of broiler chicks to threonine‐supplemented diets to 4 weeks of age

1. Two experiments were carried out to determine the response of broiler chicks to threonine‐supplemented diets between 10 and 28 d and 7 and 21 d of age, respectively.

2. In the first experiment female broiler chicks were fed on 11 experimental diets. Two iso‐energetic basal diets (diets 1 and 2) were prepared with 200 and 160 g CP/kg and 7·6 and 6·0 g threonine/kg respectively. Both diets contained 11·5 g lysine and 8·7 g sulphur‐containing amino acids/kg. Diet 3 was composed of diet 2, supplemented with all essential and non‐essential amino acids (EAA and NEAA, respectively) except threonine, to the concentrations of the amino acids in diet 1. The NEAA were added as a combination of glutamic acid and glycine. Diets 4 to 11 had the same compositions as diet 3, but contained increasing amounts of threonine.

3. For birds fed on diet 2, gain was significantly lower and food/gain ratio was significantly higher than for birds fed on diet 1. Supplementation with EAA, NEAA and threonine to the same concentrations in diet 1 resulted in a performance similar to that found on diet 1.

4. In experiment 2, male and female broiler chicks both received 10 experimental diets. Diet 1 contained 220 g CP/kg and 8.5 g threonine/kg, diet 2 contained 160 g CP/kg from natural raw materials and 6 g threonine/kg. Both diets contained 12·4 g lysine and 9·3 g sulphur‐containing amino acids/kg. Basal diet 2 was supplemented with all EAA and NEAA to the concentrations of basal diet 1, except for threonine. Diets 3 to 10 had the same compositions as the supplemented diet 2, but contained increasing amounts of threonine.

5. For male and female chicks on diet 2, gain was significantly lower and food/gain ratio significantly higher than those on diet 1. Diet 10 (160 g CP/kg plus all EAA, including threonine, and NEAA supplemented to the concentrations of diet 1) resulted in the same performance as diet 1.

6. The results indicate that, when low protein maize‐soyabean meal diets supplemented with EAA and NEAA with 13·31 MJ ME/kg were fed to male and female broiler chicks until 21 d of age, improvements in gain and food/gain ratio were obtained when the dietary threonine content was increased to 7·25 g/kg. When female chicks were fed threonine‐supplemented diets to 28 d of age, improvement in gain and food/gain ratio was obtained when the threonine concentrations were increased to 6·32 g/kg diet.

7. Curves have been fitted to the data, from which a cost‐benefit analyses can be made and an optimum threonine dose calculated, using local prices.     

Bright Food to Buy Control of Israel＇s Tnuva to Boost Dairy Sales

China＇s Bright Food Group Co., Ltd. SHMNGA.UL has struck a deal to buy control of Israel＇s largest food company,gaining new products and technology as it chases rivals that have overtaken it in China＇s fast-growing cheese and dairy markets.     

Comparison of tick resistance of crossbred Senepol × Limousin to purebred Limousin cattle

The comparison of resistance to natural tick infestation by Rhipicephalus microplus (Canestrini, 1887) of crossbred Senepol?×?Limousin and purebred Limousin cattle was investigated. The Senepol breed, originated from St Croix Island in the Caribbean is considered as a Bos taurus breed adapted to tropical conditions. Despite its B. taurus genetic background, it is believed to have a good tick resistance, but this resistance has never been assessed previously. Tick counts under natural infestation were carried out to investigate the difference of susceptibility between crossbred Senepol?×?Limousin and purebred Limousin cattle. Mixed-effect models were used to assess the effect of the breed on the number of ticks. Results show that Senepol?×?Limousin are five times less infested by ticks than purebred Limousin. These results underline the opportunity to use Senepol cattle for crossing with susceptible B. taurus breeds in tick infested areas, to combine tick resistance with beef production abilities.     

Contribution of pharmacokinetic studies to mycotoxicology—Ochratoxin A

A pharmacokinetic study of ochratoxin A in rats has demonstrated the binding of the toxin to serum albumin and its presence in all organs investigated. The acidic properties of the mycotoxin explain its absorption from the stomach and the fact that it binds to some macromolecules.Ochratoxin A is converted into the less toxic ochratoxin by the bacterial microflora present in the rat caecum and in rumen liquor, and this product of hydrolysis has been recovered from urine and faeces. However, oxhratoxin A itself is excreted in the milk of rabbits.Using the example of ochratoxin A, the author discusses the value of such investigations in the study of the contamination of the human food chain.

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Kurzfassung Das pharmako-kinetische Studium des Ochratoxins A an Ratten zeigt, dass das Toxin an das Albumin des Plasmas gebunden wird; sein Nachweis gelang in allen untersuchten Organen. Die sauren Eigenschaften des Mycotoxins machen eine Resorption im Magen sowie die Bindung an einige Makromoleküle verständlich. Das Ochratoxin A wird durch die bakterielle Mikroflora des Caecums der Ratte als auch durch Pansensaft zu Ochratoxin umgewandelt. Dieses Hydrolysat ist in Harn und Fäces der Tiere nachweisbar. Ochratoxin A jedoch wird nur mit der Milch des weiblichen Kaninchens ausgeschieden.Im Anschluss an die Beispiele diskutiert der Autor des Interesse dieser Studien bezüglich einer Kontamination in der Ernährungskette des Menschen; immerhin geben jene Ergebnisse Anlass genug für weitere gründliche Untersuchungen.

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Resume L'étude pharmacocinétique de l'ochratoxine A chez le Rat démontre la liaison de la toxine avec l'albumine plasmatique et sa présence dans tous les organes examinés. Les propriétés acides de la mycotoxine permettent d'expliquer son absorption gastrique et les liaisons avec certaines macromolécules. L'ochratoxine A est transformée en ochratoxine moins toxique par les microflores du caecum de Rat et des liquides de rumen. Ce produit d'hydrolyse est retrouvé dans l'urine et les fèces des animaux; toutefois, l'ochratoxine A est excrétée seule par le lait de la lapine.A partir de cet exemple, l'auteur discute de l'intérêt de telles études à propos du problème de la contamination de la chaîne alimentaire de l'Homme et justifie l'approfondissement de recherches complementaires.

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Riassunto Lo studio farmacocinetico dell'ochratossina A nei ratti mette in luce la relazione esistente fra la tossina e l'albumina plasmatica, nonché la sua presenza in tutti gli organi esaminati. Le proprietà acide della micotossina spiegano il suo assorbimento gastrico ed i suoi legami con talune macromolecole. L'ocratossina A è trasformata in ocratossina meno tossica, dalla microflora batterica dell'intestino cieco del ratto e dal succo gastrico. Questo prodotto idrolitico è presente nell'urina e nelle feci degli animali; peraltro l'ocratossina A è eliminato soltanto attraverso il latte della coniglia.Basandosi su questo esempio, l'autore esamina l'interesse di tali studi in relazione al problema della contaminazione della catena alimentare umana e motiva la necessità di ulteriori ricerche.

     

Reproductive Responses of Holstein–Friesian Cattle to the Climatic Conditions of Central Sudan

Data were evaluated from a purebred Holstein herd (n = 1274) kept near Khartoum, a hot and dry area, from 1990 to 1996. The mixed model procedure in SAS was used to analyse the reproductive traits. The mean gestation length, days dry, number of services per conception, days from calving to first oestrus, days from calving to conception, calving interval and breeding efficiency were 279 days, 104 days, 4.2, 85.8 days, 208.9 days, 486.2 days and 74.9%, respectively. Factors that had significant effects (p<0.01) on all the reproductive measures under study were the year and month of calving, and parity.The heritability estimates for all traits under investigation were zero. The repeatability estimates for the numbers of services per conception, days from calving to conception, days from calving to first oestrus and calving interval were 0.21±0.021, 0.12±0.024, 0.03±0.018 and 0.00, respectively. The phenotypic correlation for calving interval with numbers of service per conception was 0.05, that with days from calving to first oestrus was 0.06 and that with days from calving to conception was 0.07. Other correlations ranged from 0.00 to 0.28. The simple correlation coefficients between production and reproductive measures ranged from –0.06 to 0.45.     

Threonine requirement of White Pekin ducks from hatch to 21 d of age

1. A dose-response experiment with 5 dietary threonine concentrations (5.0, 5.8, 6.6, 7.4 and 8.2 g/kg) was conducted to estimate the threonine requirement of White Pekin ducks from hatch to 21 d of age.

2. A total of 240 one-d-old male White Pekin ducks were allotted to 5 experimental treatments and each treatment contained 6 replicate pens with 8 ducks per pen. Ducks were reared in raised wire-floor pens from hatch to 21 d of age. At 21 d of age, growth performance and intestinal morphology were determined.

3. The weight gain and feed intake of Pekin ducks increased and feed/gain of these birds decreased linearly or quadratically as dietary threonine increased from 5.0 to 8.2 g threonine/kg. Compared to ducks fed on diets containing 5.0 g threonine/kg, ducks given diets containing 7.4 g threonine/kg had higher villus height in duodenum, jejunum and ileum.

4. The threonine requirements for weight gain of White Pekin ducks from hatch to 21 d of age was estimated to be 6.72 g/kg when dietary crude protein concentration was 189.8 g/kg and threonine supply was critical for maintaining intestinal structure of these birds.     

Use of delayed‐type hypersensitivity test to diagnose brucellosis in calves born to infected dams

Summary

Calves (n = 2) born to dams with experimentally induced brucellosis, and calves (n = 4) born to dams with naturally occurring infection were examined by the delayed‐type hypersensitivity (DTH) test for possible B. abortus infection. The results were compared with the serum agglutination test, complement fixation test, and Coombs test. Five calves were nursed by their dams for 8–10 weeks after birth. One calf was separated from its dam and fed artificial milk.

Three to five months after birth, four calves tested seropositive in the serologic tests. Antibodies were detected in one calf as early as 1 week after birth. The calf fed on artificial milk was seronegative 4–5 weeks after birth. All calves reacted to the DTH test antigen from week 12 until the end of the experiment, even though serologic tests were negative. We conclude that the DTH test is a valuable technique for diagnosing Brucella in calves born to infected dams.     

Effect of increasing supplemental phytase concentration in diets fed to Hubbard × Cobb 500 male broilers from 1 to 42 days of age

Phytase supplementation beyond the standard doses used for phosphorus release has been reported to result in extraphosphoric effects by enhancing nutrient digestibility resulting in improved performance of broilers. A study was conducted to examine the effects of the progressive addition of an enhancedEscherichia Coli phytase (400–1,600 phytase units; FTU) on growth performance and carcass characteristics from 1 to 42 d of age in male broilers. One thousand four hundred Hubbard × Cobb 500 1-d-old chicks were randomly distributed into 56 floor pens (0.08 m²/bird). Seven dietary treatments were provided in a 3-phase feeding program consisting of (1) a positive control (adequate Ca and nonphytate P; PC); (2) 1 negative control (Ca and nonphytate P reduced by 0.14% and 0.13%; NC); (3 to 6) the NC diet with 4 increasing supplemental phytase concentrations (NC + 400 FTU, NC + 800 FTU, NC + 1,200 FTU, and NC + 1,600 FTU, respectively); and (7) a low-energy NC diet without phytase and xylanase (reduced 66 kcal of AME_n/kg). Body weight gain, feed conversion, mortality, weight and yield of whole carcass, abdominal fat, and pectoralis major and minor muscles were evaluated. Progressive supplementation of phytase decreased cumulative FCR linearly. Broilers fed diets containing 1,600 FTU had heavier total breast meat by 49 g compared with birds receiving the PC diets. Broilers consuming the NC + 400 FTU or the low-energy NC diet had similar growth performance and meat yield compared with birds provided PC diet. These data indicated that phytase supplementation beyond the need for phosphorus enhances growth performance and carcass characteristics.     

Transfer of tumour necrosis factor-α via colostrum to foals

This study aimed to determine whether TNF-α is transferred to equine neonates via colostrum and the relationship between TNF-α and IgG concentrations in the equine neonate. Colostrum, presuckle and postsuckle foal serum samples were collected from healthy mares and their foals. Equine TNF-α ELISA and IgG SRID kits were used to determine the concentrations of TNF-α and IgG, respectively. Statistical analysis was performed using the Spearman rank correlation. TNF-α concentrations in all presuckle foal serum were below the limit of detection in 15/16 foals and increased in postsuckle foal serum to a mean concentration of 7.7 x 10(4) pg/ml. TNF-α concentrations in postsuckle foal serum and colostrum showed significant correlation (rho=0.668; P=0.005). However, TNF-α and IgG concentrations in colostrum or postsuckle foal serum did not correlate (rho<-0.016; P>0.05). Ratios of TNF-α/IgG in colostrum or postsuckle foal serum showed significant correlation (rho=0.750; P=0.0008). These results indicate that TNF-α is transferred to the foal via colostrum absorption and may play a role in early immunity.     

Response of broiler chickens to well‐balanced protein mixtures

1. Four experiments were conducted on broiler chickens between one and three weeks of age to determine their response to dietary protein concentrations.

2. Diets prepared by serial dilution of a concentrated protein mixture, well‐balanced with respect to all essential amino acids, were fed in three experiments, while in a fourth experiment, a lysine‐deficient protein mixture was used.

3. Response curves relating body‐weight gain to increasing concentrations of protein and of lysine intake are presented.

4. A table is presented from which optimum protein intakes can be calculated according to changes in input and output costs and changes in growth potential of the chickens.     

Breeding for resistance to footrot – the use of hoof lesion scoring to quantify footrot in sheep

So that genetic studies can be undertaken on footrot in sheep, it is necessary that a reliable and repeatable method to categorise the phenotype is available. This paper summarises the methods used and results obtained from 1600 hoof lesion scores of 100 mixed-age ewes independently scored twice by two trained operators. Using a 5-pont scale describing the severity of foot lesions, residual correlations were used to assess agreement between scorers and scoring occasions. Data were analysed using both zero-1 and continuous data methods. The average prevalence of any score >0 was 15%, and of scores >1 was 12%. The residual correlation between scorers for SUM_FR was 0.87 and between scoring occasions it was also 0.87, indicating high repeatability or agreement both within and between scorers. No significant differences were detected between scorers or between scoring occasions for any of the traits analysed, or different analytical methods used.     

The effect of feeding low‐protein diets to pullets from hatch to point‐of‐lay and the quantitative restriction of food during the subsequent laying period

Pullets from two commercial breeds were fed on diets of similar energy content but with 19% or 16% crude protein to 8 weeks of age and from 8 to 20 weeks of age on one of three isoenergetic diets containing either 12, 14 or 16% crude protein. At 20 weeks the birds were offered a conventional layers’ diet containing 16% crude protein either ad libitum or on a daily food intake of 100 g for a further 32 weeks.

The results indicate that with certain breeds the dietary protein levels can be lowered to approximately 16% during the o to 8‐week period and to approximately 12% during the 8 to 20‐week period without adversely affecting egg production. However, variations in the laying performance of the different breeds appear to be dependent on the amount of protein fed in the first eight weeks of life. Significant breed effects were observed throughout the experiment and although restricted feeding during the laying period substantially reduced the food intake it also had a detrimental effect on the rate of egg production and on the total weight of eggs produced.     

Aspects of metabolism related to the occurrence of skin lesions in biotin‐deficient chicks

1. Chicks were fed on biotin‐deficient low‐ and high‐protein diets supplemented with increasing concentrations of biotin.

2. Biotin deficiency decreased hepatic activity of pyruvate carboxylase [EG 6.4.1.1] but activity of acetyl‐CoA carboxylase [EG 6.4.1.2] was comparatively unaffected.

3. Increasing dietary protein increased the severity of biotin deficiency as assessed by skin lesions and decreased plasma biotin concentrations.

4. The severity of the skin lesions over all the treatments was most closely related to plasma biotin concentration.     

Physiopathological Effects of the Administration of Chronic Cyanide to Growing Goats – A Model for Ingestion of Cyanogenic Plants

Ingestion of cyanogenic plants, such as cassava and sorghum, has been associated with goitre and tropical pancreatic diabetes in both humans and animals. Thus, the objective of the present study was to determine the toxic effects on the thyroid and pancreas in growing goats of prolonged exposure to potassium cyanide (KCN). Thirty-four male goats were divided into five groups dosed with KCN at 0 (control), 0.3, 0.6, 1.2 or 3.0 mg/kg daily for 5 months. Blood samples were obtained in order to determine the glucose, cholesterol, thyroxine (T₄), triiodothyronine (T₃) and thiocyanate concentrations and for haematological studies; pancreas and thyroid gland were collected for histopathological study. The group receiving the highest dose of cyanide showed lower body weight gains and carcase weights and a decrease in plasma T₃ concentrations compared to the control group. Reabsorption vacuoles in follicular colloid and normocytic normochromic anaemia were observed in the experimental animals. Inhibition of peripheral conversion of T₄ to T₃ is suggested. However, no diabetogenic effects were observed.     

Effect of age of donor on the responsiveness of dispersed and cultured chicken anterior pituitary cells to GnRH‐I

1. The aim of this study was to devise a method to prepare and culture anterior pituitary cells from juvenile and adult chickens in order to investigate mechanisms controlling gonadotrophin‐releasing hormone‐I (GnRH‐I) ‐induced luteinising hormone (LH) release in vitro.

2. The optimum culture medium for maintaining gonadotroph responsiveness to GnRH‐I was bicarbonate‐buffered and phenol red‐free Medium 199 supplemented with 10% foetal calf serum.

3. Cultured pituitary cells from juvenile chickens were more responsive to GnRH‐I than cells from adult cockerels, while no LH was released in response to GnRH‐I from pituitary cells from laying hens.

4. Cultured pituitary cells from adult chickens of both sexes released LH in response to 12‐O‐tetradecanoyl‐13‐phorbol acetate (TPA), an activator of an enzyme involved in intracellular signalling, protein kinase C.

5. It is concluded that freshly‐dispersed and cultured gonadotrophs from adult chickens do not regain their responsiveness to GnRH‐I as well as freshly‐dispersed and cultured gonadotrophs from juvenile chickens. It appears that the stimulus‐secretion coupling pathway between the GnRH‐receptor and the activation of protein kinase C in gonadotrophs from adult chickens is more easily disrupted by dispersion and culture than in gonadotrophs from juvenile chickens.