Dog food production using curcumin as antioxidant: effects of intake on animal growth, health and feed conservation.

The objectives of this study were to produce dog food containing curcumin replacing synthetic antioxidants, to evaluate its beneficial effects on animal growth and health. Curcumin (100 mg/kg) was added after the extrusion process along with the other micronutrients. The final concentration of curcumin was 32.9 mg/kg. The control feed was composed of the same ingredients without curcumin. After a storage of 6 months, feed composition and pH did not differ; however, the feed with curcumin showed lower protein oxidation, lipid peroxidation and higher total antioxidant capacity. After 2 months of feed production, 12 young Beagle dogs received either curcumin-containing food (n = 6)  or the control diet (n = 6). The animals were fed twice a day using individual kennels. Blood samples were taken on d 1, 35 and 42. During the first 30 d of the study, the animals had natural infectious diseases that were controlled with anti-protozoals and antibiotics. Greater numbers of red blood cells were observed in dogs fed with curcumin (d 35 and 45), and there were greater numbers of white blood cells as a consequence of increased neutrophils on d 42. At the end of the experiment, a significant reduction in the number of lymphocytes was observed in dogs that ingested curcumin (d 42), suggesting an anti-inflammatory effect, manifested as a decrease in globulin levels. In the final 15 d of the experiment, the animals were clinical healthy. Higher serum levels of glucose, urea, triglycerides and cholesterol were observed in dogs fed with curcumin. Curcumin increased the activity of several antioxidant enzymes in addition to non-protein thiols and the total antioxidant capacity in the serum, consequently reducing levels of oxygen reactive species. Curcumin supplementation of dogs did not favour growth or weight gain. Neverthless, it was concluded that curcumin improved animal health, with emphasis on the stimulation of the antioxidant system and evidence of an anti-inflammatory effect.

Factorial calculation of calcium and phosphorus requirements of growing dogs.

Calcium and phosphorus requirements for growing dogs can be calculated by different methods. The current standard feeding recommendations are based on experimental data derived from young giant breed puppies. In order to determine the absolute requirement, an extrapolation via metabolisable energy requirement is recommended. Another approach is to calculate the requirement factorially, taking into account the endogenous losses and the amount of calcium and phosphorus retained due to tissue accretion during growth as well as the expected availability of these nutrients. The working hypothesis was that both methods are valid and lead to comparable results in young puppies of a high mature body weight (BW). Yet, deviations for other age and mature BW groups were expected. Thus, the aim of the present study was to compare the results of both methods using exemplary puppies of different age and mature BW groups. The hypotheses could be verified for calcium. The extrapolated requirements overestimate the factorial requirements by up to 59.7% for puppies <60kg mature BW and/or >6 months of age. In case of phosphorus requirement, the deviations between both methods are overall very high in all stages. Taking into account the potentially harmful effects of calcium and phosphorus excess, the feeding recommendations based on the extrapolation should be reconsidered.

Effects of low phosphorus supply on the availability of calcium and phosphorus, and musculoskeletal development of growing dogs of two different breeds.

To investigate the impact of a selective reduction in dietary phosphorus (P) supply on healthy growing dogs, a total of 23 Beagles and 30 Foxhound crossbreds (FBI) were used in a feeding trial between 6 and 24 weeks of age. Sixteen Beagles and 19 FBI were fed with selectively reduced P concentrations (low phosphorus, LP). The remaining puppies received a completely balanced control diet (CON). With these diets, the P supply in the Beagles at the age of 12 weeks added up to 2.5 ± 0.6 (LP) and 9.8 ± 1.4 g P/kg DM (CON), and in the FBI 4.3 ± 0.9 (LP) and 13.0 ± 1.6 g P/kg DM (CON). Therefore, the LP Beagles received an average of 33 ± 11% of the recommended daily allowances (RDA) of P, the LP FBI 41 ± 11%. The calcium (Ca) concentration stayed unaltered and led to a Ca/P ratio above the recommended range of 1.3/1 to 2/1. The apparent digestibility (aD) of phosphorus was reduced in the LP Beagle; otherwise, the aD of both minerals was not affected by the P concentration of the diet. The renal excretion of P was reduced to zero in both LP groups while the renal calcium excretion increased significantly. Several of the puppies from both breeds showed impaired appetite, growth, skin and fur quality, and a few also clinically showed relevant signs of a disturbed musculoskeletal system after the LP feeding. A rapid loss of muscle strength and posture within hours led to severe deviation of the limb axis with hyperflexion of the joints but no radiological aberrations or signs of pain. Immediate transition of affected puppies to a balanced diet with sufficient phosphorus resulted in a complete recovery of the puppies in less than one month. The results demonstrate the importance of an adequate P supply on the healthy development of growing dogs.

Inadequate passive immune transfer in puppies: definition, risk factors and prevention in a large multi-breed kennel.

The prevalence of neonatal mortality is high in the canine species and far from well-studied. In most domestic neonates, an appropriate colostrum intake is a key element of the control of neonatal mortality. The aim of this study was to evaluate the impact of passive immune transfer on puppy mortality, assessed through serum immunoglobulin G (IgG) concentration at 2 days of age. Factors impacting passive immune transfer and the value of an oral immunoglobulin supplementation to prevent it were also analyzed. A total of 149 puppies from 34 litters (12 breeds) within one breeding kennel were included. Blood samples were collected at 2 days of age and colostrum was collected from their dams 1 day after whelping to assay IgG concentration. Puppies were weighed at birth and at 2 days of age for calculation of growth rate. Mortality was recorded until 3 weeks of age. Seventy randomly assigned puppies were orally supplemented with hyper-immunized adult plasma twice within the first 8h of life. IgG concentration at 2 days of age was significantly correlated with weight gain during the first 2 days of life. The multivariable model with litter as a random effect demonstrated that neonatal mortality was not influenced by breed size, sex, supplementation, litter size, nor colostrum IgG concentration, but by puppy IgG concentration at 2 days of age. According to the ROC curve, the minimal IgG concentration at and below which puppies were at higher risk of death was determined at 230 mg/dl. Puppy IgG concentration was significantly associated with growth rate, but not with breed size, sex, supplementation, litter size or colostrum IgG concentration in a multivariable model with litter as a random effect. This study demonstrates that neonatal mortality in puppies is related to the quality of passive immune transfer. The oral supplementation with hyper-immunized canine plasma neither decreased risk of mortality, nor improved serum IgG concentration at 2 days of age in puppies. Attention must thus be paid to early colostrum intake to control the neonatal mortality in puppies.

Evaluation of cognitive learning, memory, psychomotor, immunologic, and retinal functions in healthy puppies fed foods fortified with docosahexaenoic acid-rich fish oil from 8 to 52 weeks of age.

OBJECTIVE: To assess effects of foods fortified with docosahexaenoic acid (DHA)-rich fish oil on cognitive, memory, psychomotor, immunologic, and retinal function and other measures of development in healthy puppies. DESIGN: Evaluation study. ANIMALS: 48 Beagle puppies. PROCEDURES: Puppies were assigned to 3 groups after weaning (n = 16/group) and received 1 of 3 foods (low-DHA, moderate-DHA, or high-DHA food) as their sole source of nutrition until 1 year of age. Visual discrimination learning and memory tasks, psychomotor performance tasks, and physiologic tests including blood and serum analysis, electroretinography, and dual-energy x-ray absorptiometry were performed at various time points. Anti-rabies virus antibody titers were evaluated 1, 2, 4, and 8 weeks after vaccination at 16 weeks of age. RESULTS: Foods had similar proximate analysis results but varied in concentration of DHA from fish oil; the high-DHA food also contained higher concentrations of vitamin E, taurine, choline, and l-carnitine than did other foods. The high-DHA group had significantly better results for reversal task learning, visual contrast discrimination, and early psychomotor performance in side-to-side navigation through an obstacle-containing maze than did the moderate-DHA and low-DHA groups. The high-DHA group had significantly higher anti-rabies antibody titers 1 and 2 weeks after vaccination than did other groups. Peak b-wave amplitudes during scotopic electroretinography were positively correlated with serum DHA concentrations at all evaluated time points. CONCLUSIONS AND CLINICAL RELEVANCE: Dietary fortification with fish oils rich in DHA and possibly other nutrients implicated in neurocognitive development following weaning improved cognitive, memory, psychomotor, immunologic, and retinal functions in growing dogs.

Timing of the intestinal barrier closure in puppies.

As puppies are born with very low immunoglobulin concentrations, they rely on passive immune transfer from ingested colostrum to acquire a protective immunity during the first few weeks of life. The purpose of this study was to describe the timing of gut closure in canine neonates. Twenty-two Beagle puppies received 3 ml of standardized canine colostrum at 0, 4, 8, 12, 16 or 24 h after birth using a feeding tube. Blood immunoglobulins G (IgG, M and A) were assayed 0, 4 and 48 h after colostrum ingestion. IgG absorption rate was significantly affected by the time of colostrum administration, and the IgG concentrations in puppies serum 48 h after administration were significantly higher when colostrum was ingested at 0-4 h of age than at 8-12 h or 16-24 h (1.68 ± 0.4, 0.79 ± 0.07 and 0.35 ± 0.08 g/l, respectively; p < 0.001). In the canine species, gut closure seems thus to begin as early as 4-8 h after birth and to be complete at 16-24 h. Consequently, this phenomenon appears to occur earlier in puppies than in most other species.

Composition and use of puppy milk replacers in German Shepherd puppies in the Netherlands.

Enostosis or eosinophilic panosteitis is a common disease in young growing large-breed dogs, such as the German Shepherd, and the risk of developing the disease by 3-4 months of age is increased by a high calcium intake. The aim of the study was to investigate whether German Shepherd puppies raised on milk replacers receive more calcium and/or vitamin D than their requirements in the pre-weaning period and thus are at increased risk of developing skeletal diseases. To this end, we surveyed German Shepherd breeders in the Netherlands about the use of puppy milk replacers (PMR). The metabolizable energy, calcium, phosphorus and vitamin D content of the eight most used PMR were compared with that of bitch milk, as reported in the literature. The protein and fat content of most PMR were somewhat lower (range 24.4-33.2 g per 100 g on dmb and 18.3-37.5 g per 100 g on dmb respectively) compared with bitch milk (31.9 and 40.2 g on dmb respectively). The vitamin D content of one of the PMR samples was sevenfold the level recommended by the NRC (Nutrient Requirements of Dogs and Cats, National Academy Press, 2006) and threefold the average level of bitch milk. The clinical relevance of this high amount is questionable, as bitch milk contains mainly 25-hydroxy-vitamin D [3843 µg (96.1 IU) per 100 g on dmb] and only limited amounts of vitamin D [524 µg (13.3 IU) per 100 g on dmb], as was determined in this study. Dutch German Shepherd breeders tended to overfeed their puppies. We calculated that misguided use of PMR can increase the risk of excessive calcium, phosphorus and possibly vitamin D intake during a vulnerable period, potentially giving rise to bone and cartilage problems later in life.

Factors that modify the effect of excess calcium on skeletal development in puppies.

Developmental skeletal problems are often connected to mistakes in feeding, i.e. a deficiency or excess supply of nutrients, especially minerals. The energy consumption, the resulting growth intensity and the breed of animals are also known as factors that influence developmental orthopaedic diseases. In most clinical trials, excess Ca was connected to alterations in normal, healthy skeletal development, which led to severe clinical symptoms in some dogs, subclinical changes in the radiographic or histological examinations in other animals, or even no observable symptoms. These results correspond to practical experience in the field of clinical nutrition consultation, since excess Ca has been shown to have various impacts in growing dogs. The present review of results published in the literature and from my own trials led to the hypothesis that P is an important co-factor that can alleviate or aggravate the development of skeletal problems in growing dogs.

Análisis morfométrico del número de odontoblastos en recubrimientos directos con hidróxido de calcio y propóleos en canes / Morphometric analysis of odontoblasts number in direct capping with calcium hydroxide and propolis in dogs

El propóleos se ha utilizado en medicina desde épocas antiguas, una de sus indicaciones en medicina oral y odontológica es como material de recubrimiento directo. Así, el objetivo de este estudio fue cuantificar la neoformación odontoblástica en piezas dentarias de canes en recubrimientos directos. Se realizaron perforaciones en un total de 12 piezas dentarias, la mitad de las cuales fueron recubiertas con propóleos y la otra mitad con hidróxido de calcio. En todos los casos se obturaron las piezas dentarias con cemento de vidrio-ionómero. Al cabo de dos semanas, se realizaron las extracciones de las piezas dentarias, fijándolas en formalina tamponada; se efectuaron cortes histológicos de las piezas, los cuales se tiñeron con hematoxilina-eosina, con el fin de poder realizar la cuantificación de los núcleos odontoblásticos presentes tanto en las zonas alejadas de la perforación, como en las zonas cercanas a las lesiones. Se observó una similar actividad odontoblástica en las zonas cercanas a las lesiones al utilizar cualquiera de los dos materiales (p=0,9325), diferenciándose solamente en la disposición de las células neoformadas, que en el caso de utilizar propóleos fueron en empalizada, semejante a las zonas sanas, en cambio, al utilizar hidróxido de calcio no se observó dicho ordenamiento.

Since ancient times, propolis has been used in medicine, while in oral medicine and dentistry it has been indicated as a direct capping material.The aim of this study was to quantify the odontoblast activity in drilling holes on dog's teeth (canine and incisor) during direct capping.Perforations were carried out in a total sample of 12 dental pieces. In half of the sample teeth were capped with propolis, and in the other half with calcium hydroxide. In all cases teeth were obturated with glass ionomer cement. Extraction of the teeth was realized after two weeks, and teeth were fixed in buffered formalin. Histological cuts of the pieces were made and stained with hematoxylin-eosin in order to carry out quantification of nuclei presence in healthy areas (away from the perforation, as well as in areas adjacent to injuries. Results showed similar odontoblast activity while using either of the materials, (p=0.9325), only differing in the arrangement of newly formed cells which in the cases where propolis was used, were palisading, similar to healthy areas. On the other hand, the same order was not observed when calcium hydroxide was used.

Effects of dietary scFOS on immunoglobulins in colostrums and milk of bitches.

Fructo-oligosaccharides (scFOS) are prebiotic ingredients that improve protection against pathogens probably through promoting the growth of gastrointestinal bacteria-like Bifidobacteria and Lactobacilli: this stimulation may lead to a better development of immune repertoire and/or stimulation of the local immune response. According to the existence of the immune entero-mammary link, we were wondering if the dietary supplementation with scFOS could enhance the mucosal immunoglobulin level in mammary secretions. Results in this study show that bitches supplemented with scFOS exhibit higher colostrum and milk IgM content without concomitant effect on IgG1, IgG2 and IgA. In addition, intranasally immunized puppies exhibited a trend to higher Bordetella bronchiseptica-specific IgM immune response. The dietary supplementation with scFOS increased the IgM level in colostrums and milk of bitches by mechanisms which remain to be elucidated.

Primary hair growth in dogs depends on dietary selenium concentrations.

Selenium (Se) plays an important role in hair growth. The objective of this study was to investigate the effect of dietary selenium concentration on hair growth in dogs. Thirty-six beagles were stratified into six groups based on age, gender and body condition score. The dogs were fed a torula yeast-based canned food for 3 weeks. Then the dogs were fed varying amounts of selenium supplied as selenomethionine for an additional 24 weeks. Analysed selenium concentrations in the experimental foods for the six groups were 0.04, 0.09, 0.12, 0.54, 1.03 and 5.04 mg/kg dry matter respectively. Body weight and food intake were not affected by the selenium treatments. Serum selenium concentration was similar initially but was significantly different at the end of the study among groups. Dietary selenium concentration below 0.12 mg/kg diet may be marginal for an adult dog. Dietary treatment had no effect on serum total thyroxine (TT(4)), free thyroxine (FT(4)), and free 3,3',5-triiodothyronine (FT(3)). There was a significant diet and time interaction (p = 0.038) for total 3,3',5 triiodothyronine (TT(3)). Hair growth was similar among groups initially but significantly reduced in dogs fed diets containing 0.04, 0.09 or 5.04 mg Se/kg when compared with 0.12, 0.54 and 1.03 mg Se/kg at week 11 (p < 0.05) and week 22 (p = 0.061). These results demonstrated that both low and high selenium diets reduce hair growth in adult dogs.

The selenium requirement of the puppy.

Current selenium (Se) recommendations for the puppy are based on extrapolation from other species (0.11 mg Se/kg diet). The purpose of this study was to experimentally determine the Se requirement in puppies. Thirty beagle puppies (average = 8.8 weeks old) were utilized in a randomized complete block design with age, litter and gender used as blocking criteria. Puppies were fed a low Se (0.04 mg Se/kg diet) torula yeast-based diet for 14 days (pre-test period) after which this same diet was supplemented with five levels of Na2SeO3 for 21 days (experimental period) to construct a response curve (0, 0.13, 0.26, 0.39 or 0.52 mg Se/kg diet). Response variables included Se concentrations and Se-dependent glutathione peroxidase activities (GSHpx) in serum as well as serum total triiodothyronine (TT3), serum total thyroxine (TT4) and serum free T4 (FT4). No significant changes in food intake and body weight gain occurred, and no clinical signs of Se deficiency were observed. A breakpoint for serum GSHpx could not be determined in our study due to analytical difficulties. A broken-line, two-slope response in serum Se occurred with a breakpoint at 0.17 mg Se/kg diet. When Se from the basal diet was added to this estimate, the breakpoint for serum Se equated to 0.21 mg Se/kg diet. TT3 increased linearly with increasing Se intake, whereas TT4 was unchanged. However, the ratio of TT4 : TT3 decreased linearly in response to supplemental Se. In summary, although we estimated the selenium requirement for the puppy based on serum Se, our 0.21 mg Se/kg diet estimate is higher than that seen for adult dogs, kittens, rats or poultry (0.13, 0.15, 0.15 and 0.15 mg Se/kg diet respectively). This difference may be due to the fact that GSHpx was used as the biomarker of Se status.

Effects of plasmid-mediated growth hormone releasing hormone supplementation in young, healthy Beagle dogs.

Our study focused on the evaluation of the pharmacological and toxicological effects of plasmid-mediated GHRH supplementation with electroporation in normal adult dogs over a 180-d period. Twenty-eight dogs (< 2 yr of age) were randomized to four groups. Three groups (four dogs/sex for each group) were treated with ascending doses of GHRH-expressing plasmid: 0.2, 0.6, and 1 mg. One group (two dogs of each sex) served as the control. Clinical observations and body weights were recorded. Hematological, serum biochemical, and urine analyses were performed. Serum IGF-I, ACTH, and insulin were determined. Necropsies were performed on d 93 and 180; organs were weighed and tissues were fixed and processed for light microscopy. Selected tissues were used to assess plasmid biodistribution on d 93. At all doses, plasmid GHRH caused increased weight gain (P < 0.001), without organomegaly. Serum glucose and insulin in fasted dogs remained within normal ranges at all time points. Adrenocorticotropic hormone was normal in all groups. Significant increases in number of red blood cells, hematocrit, and hemoglobin (P < 0.01) were observed. In conclusion, our study shows that plasmid-mediated GHRH supplementation is safe in electroporated doses up to 1.0 mg in young healthy dogs.

Hormonal regulation of calcium homeostasis in two breeds of dogs during growth at different rates.

Growing giant-breed dogs are more susceptible to developing skeletal disorders than small-breed dogs when raised on diets with deficient or excessive Ca content. Differential hormonal regulation of Ca homeostasis in dogs with different growth rates was investigated in Great Danes (GD, n = 9) and Miniature Poodles (MP, n = 8). All animals were raised on the same balanced diet and under identical conditions. Calciotropic and growth-regulating hormones were measured. Production and clearance of 1,25-dihydroxycholecalciferol (1,25[OH]2D3) were investigated with the aid of [3H]-1,25(OH)2D3 and renal messenger RNA abundance of 1 alpha-hydroxylase and 24-hydroxylase. Intestinal, renal, and skeletal Ca handling were evaluated with the aid of 45Ca balance studies. Skeletal development was evaluated by radiology and histomorphometry. Great Danes had greater (P < 0.001) growth rates than MP, as indicated by the 17-fold greater body weight gain, by increased longitudinal growth reflected in the increased (P < 0.05) gain in length of the radius and ulna, and by increased (P < 0.001) growth plate thickness. These findings were accompanied in GD by greater (P < 0.05) plasma GH and IGF-I concentrations. Effects were observed for vitamin D3 metabolism, such as greater (P < 0.01) plasma 1,25(OH)2D3 concentrations due to decreased (P < 0.01) clearance rather than increased production of 1,25(OH)2D3, and decreased (P < 0.01) plasma 24,25-dihydroxycholecalciferol (24,25[OH]2D3) concentrations likely due to competitive inhibition of the production of 24,25(OH)2D3. These findings were accompanied in both breeds by a limited hormonal regulation of Ca and P absorption at the intestinal level, and in GD by increased (P < 0.05) renal reabsorption of inorganic P (Pi) compared with MP, resulting in greater (P < 0.01) Pi retention and greater (P < 0.01) plasma Pi concentrations. Bone turnover, resorption, and formation were greater (P < 0.01) in GD than in MP. In addition, GD had more irregular (P < 0.01) growth plates than MP, accompanied by disorders of endochondral ossification. It is suggested that in GD, increased calcitonin levels and/or a relative deficiency in 24,25(OH)2D3 at the growth-plate level may both be responsible for the retarded maturation of chondrocytes, resulting in retained cartilage cones and osteochondrosis, and this may be a pathophysiological factor for the increased susceptibility of large breed dogs to developing skeletal disorders.

Dietary 135-fold cholecalciferol supplementation severely disturbs the endochondral ossification in growing dogs.

The effects of excessive non-toxic dietary Vitamin D(3) supplementation on Ca homeostasis with specific effects on endochondral ossification and skeletal remodeling were investigated in a group of growing Great Dane dogs supplemented with cholecalciferol (Vitamin D(3); HVitD) versus a control group (CVitD) (1350 microg versus 11.4 microg Vitamin D(3) per kilogram diet) from 6 to 21 weeks of age. There were no differences between groups in plasma concentrations of total Ca, inorganic phosphate, growth hormone, and insulin-like growth factor I and no signs of Vitamin D(3) intoxication in HVitD. For the duration of the study in HVitD compared to CVitD, plasma levels of parathyroid hormone (PTH) decreased, calcitonin (CT) increased, 25-hydroxycholecalciferol [25(OH)D(3)] increased 30- to 75-fold, 24,25-dihydroxycholecalciferol [24,25(OH)(2)D(3)] increased 12- to 16-fold, and 1,25-dihydroxycholecalciferol [1,25(OH)(2)D(3)] decreased by approximately 40%. The latter was attributed to the two-fold increased metabolic clearance rate in the HVitD versus CVitD accompanied by the absence of the anabolic effect of PTH on the production of 1,25(OH)(2)D(3). Fractional Ca absorption (alpha) did not differ between groups at 8 and 14 weeks of age, whereas at 20 weeks of age alpha increased by only 16.4% in HVitD compared to CVitD. Excessive non-toxic Vitamin D(3) supplementation resulted in decreased bone remodeling and focal enlargement of the growth plate with morphology resembling those induced by administration of CT. Hypercalcitoninemia and the imbalanced relationship between 1,25(OH)(2)D(3) and 24,25(OH)(2)D(3) are potent candidates for the disturbed endochondral ossification.

Effect of lactobacillus supplementation on growth and nutrient utilization in mongrel pups.

Effect of lactobacillus supplementation was studied in eight Mongrel pups of about 10 weeks of age with a mean body weight of 5.2 kg divided into two equal groups, control (group C) and a probiotic supplemented group (group L). Both groups received the same feed (biscuit) which was for group L supplemented with 2 x 10(7) cfu of a Lactobacillus acidophilus strain. The feeding trial lasted 13 weeks and included a digestibility trial of six day during which feed and faeces were collected to assess intake and digestibility of nutrients. Growth was recorded as weekly live weight change and the physical, chemical and microbiological characteristics of stool were examined periodically to assess the effect of lactobacillus on intestinal health. The biscuits contained 89% DM, 32.6% CP, 5.8% ash and 12.7% EE with TDN, GE and ME content of 890 g, 19.6 MJ and 14.6 MJ per kg DM, respectively. The DM, OM, CP and GE digestibilities were between 76% to 79% and the EE digestibility was 93%. The CF digestibility was negligible (22%). There were no significant differences between the two groups. There was an appetite stimulation and a relatively higher DM intake (10 to 15%) which induced higher daily gain, 102 g in group L vs. 92 g in group C up to 19 weeks of age, the difference declined thereafter. The average daily gain during the whole period was 74.5 +/- 8.0 g and 81.6 +/- 6.0 g in group C and L, respectively, and the difference was statistically non-significant (P > 0.05). The stools showed similar physical properties and composition with acidic pH in both groups. Lactobacillus supplementation caused a competitive establishment in the gastrointestinal tract of pups. It can be concluded that lactobacillus supplementation shows a positive effect during active growth phase (up to 4.5 months of age), which became insignificant in the later period of life.

Effects of diets with different calcium and phosphorus contents on the skeletal development and blood chemistry of growing great danes.

The skeletal development of three groups of great dane dogs, fed a diet composed according to the published nutritional requirements for dogs (controls) or with increased calcium or calcium and phosphorus content, was examined radiographically, histologically and biochemically. The diets were fed from the time the dogs first began eating food in addition to their dam's milk, until they were 17 weeks old. Thereafter, the calcium and phosphorus intakes of the dogs in the high calcium groups were normalised for a further 10 weeks. The dogs fed the high calcium diet without a proportionally high phosphorus intake became hypercalcaemic and hypophosphataemic, and had severe disturbances in skeletal development, growth, and mineralisation which were typical for rickets. After their calcium intake was normalised the lesions of rickets resolved but osteochondrotic lesions became apparent. The dogs fed the high calcium and phosphorus diet became slightly hypophosphataemic, their growth was retarded, and they had disturbances in skeletal development resembling osteochondrosis, which had only partly resolved after 10 weeks on the normal calcium and phosphorus diet.

Mineral metabolism in healthy geriatric dogs.

To study mineral metabolism in geriatric dogs, parathyroid hormone, calcitriol, ionised calcium, phosphorus, blood urea nitrogen and creatinine were evaluated in 35 geriatric dogs (> 10 years) and in 20 young adult dogs (2-5 years). Parathyroid hormone levels were within the normal range in both groups, but values (mean +/- SEM) were greater in the old dogs (34.8 +/- 3.6 vs 21.2 +/- 2.3 pg ml(-1), P=0.005). Calcitriol and ionised calcium were similar in the two groups, and the values for both parameters were within the normal reference range. Plasma phosphorus levels were in the normal range in both groups but tended to be greater in the older dogs (P=0.09). While blood urea nitrogen was similar in the two groups, creatinine levels (mean +/- SEM) were higher in the young dogs (82.2 +/- 3.5 vs 101.7 +/- 4.4 micromol litre(-1)). Even when the dogs were matched for weight, plasma creatinine concentration was still greater in the younger dogs. In conclusion, an increase in parathyroid hormone without changes in calcium, phosphorus and calcitriol has been identified in geriatric dogs.

Changes in histomorphometric values of iliac trabecular bone and serum biochemical constituents related to bone metabolism in beagle dogs during growth.

Changes in histomorphometric values of iliac trabecular bone and serum biochemical constituents related to bone metabolism in normal beagle dogs during growth were examined. A total of 90 dogs (male; 46, female; 44) aged 3, 6, 9, 12 and 24 months, were used. Each dog was injected with tetracycline hydrochloride and calcein for double bone labeling in order to quantitatively measure dynamic as well as static parameters in bone histomorphometry and a part of the ilium was later removed. The measurements on cancellous bone areas of undecalcified iliac sections were performed with a semiautomatic image analyzer. There were no sex significant differences in histomorphometric values except for mineralization lag time at the age of 3 months. In the static parameters, bone volume and mean trabecular thickness increased from 3 to 9 months of age. Bone surface area and mean osteoid thickness increased up to 6 months. Osteoid volume and osteoid surface area decreased up to 6 months of age. As to the dynamic parameters, the mineral apposition and bone formation rates decreased from 3 to 12 months of age. Mineralization lag time increased from 3 to 9 months of age. However, high bone surface area values in both sexes and low osteoid thickness values in females were seen at the ages of 9 and 12 months. Low values of trabecular thickness in both sexes, osteoid thickness and mineralization lag time in males and mineral apposition rate in females were also noted at the age of 12 months. Serum total calcium did not show any specific tendency.(ABSTRACT TRUNCATED AT 250 WORDS)