Gelatin Diet Research Articles

Effects of different protein sources in low-phosphorus diets on calculated basal endogenous loss of phosphorus by growing pigs

The objective of this experiment was to test the hypothesis that the basal endogenous loss (BEL) of P from pigs fed a diet containing spray dried plasma, casein, or potato protein concentrate is not different from that of pigs fed a diet containing gelatin. Forty pigs (body weight: 19.34 kg; SD = 0.80) were housed individually in metabolism crates and allotted to four low-P diets using a completely randomized block design with two blocks of 20 pigs and five pigs per diet in each block. Diets were based on cornstarch and sucrose and contained 200 g/kg gelatin, 200 g/kg spray dried plasma, 185 g/kg casein, or 200 g/kg potato protein concentrate. With the exception of Ca and P, diets were formulated to meet requirements of all nutrients. Feces and urine samples were collected for 4 d following a 5-d adaptation period. Fecal samples were dried and ground, and fecal and urine samples were analyzed for P. Data were analyzed using a model that included diet as fixed effect and block as random effect. Results indicated that feed intake and fecal excretion of dry matter were greater (P < 0.05) in pigs fed diets containing spray dried plasma, casein, or potato protein concentrate compared with pigs fed the gelatin diet, with pigs fed potato protein concentrate having the greatest (P < 0.05) excretion. The apparent total tract digestibility (ATTD) of dry matter was least (P < 0.001) in pigs fed the diet containing potato protein concentrate, but there were no differences among gelatin, spray dried plasma, and casein diets. The ATTD of P was greater (P < 0.001) in pigs fed diets containing spray dried plasma or casein compared with pigs fed gelatin or potato protein concentrate diets. The BEL of P was not different between the gelatin and casein diets (i.e., 176 and 234 mg/kg dry matter intake), but pigs fed diets containing spray dried plasma or potato protein concentrate had greater (P < 0.001) BEL of P (i.e., 338 and 374 mg/kg dry matter intake) compared with pigs fed gelatin or casein diets. In conclusion, the BEL of P was greater if calculated from diets containing spray dried plasma or potato protein concentrate compared with gelatin. However, casein may be an alternative to gelatin to estimate the BEL of P because casein provides a greater amount of P compared with gelatin, which compensates for the deficient level of P in gelatin, but does not affect the BEL of P.

123 Effects of Different Protein Sources Containing Highly Digestible Phosphorus on the Basal Endogenous Loss of Phosphorus

Abstract The objective of this experiment was to test the hypothesis that the basal endogenous loss of P from pigs fed a diet containing blood plasma, casein, or potato protein concentrate is not different from that of pigs fed a diet containing gelatin. Pigs (n = 40; body weigh =: 19.34 kg) were housed in metabolism crates and were randomly allotted to four low-P diets containing 20% gelatin, 20% blood plasma, 18.5% casein, or 20% potato protein concentrate. With the exception of Ca and P, diets were formulated to meet the requirements for 11 to 25 kg pigs. Feces and urine samples were collected separately for 4 d following a 5-d adaptation period. Feces samples were dried, ground, and analyzed for Ca and P, and urine samples were also analyzed for Ca and P. Data were analyzed using a model that included diet as fixed effect and replicate as random effect. Results indicated that feed intake and fecal excretion of dry matter were greater (P &amp;lt; 0.05) in pigs fed diets containing blood plasma, casein, and potato protein concentrate compared with pigs fed the gelatin diet, with pigs fed potato protein concentrate having the greatest (P &amp;lt; 0.05) excretion (Table 1). The apparent total tract digestibility of dry matter was least (P &amp;lt; 0.001) in pigs fed the diet containing potato protein concentrate, but there were no differences among gelatin, blood plasma, and casein diets. No differences were observed in the standardized total tract digestibility of P among diets. Basal endogenous loss of P was not different between the gelatin and casein diets, but pigs fed diets containing blood plasma or potato protein concentrate had greater (P &amp;lt; 0.001) basal endogenous loss of P compared with pigs fed gelatin or casein diets. In conclusion, the basal endogenous loss of P was greater in diets containing blood plasma and potato protein concentrate compared with gelatin. However, casein could be an alternative to gelatin to estimate the basal endogenous loss of P because casein provides a greater amount of P compared with gelatin that compensates for the deficient level of P in gelatin, but does not affect values for the basal endogenous loss of P.

Relative Biopotency of Dietary Ergocalciferol and Cholecalciferol and the Role of and Requirement for Vitamin D in Rainbow Trout (Salmo gairdneri)

A growth assay was conducted for six consecutive 28-day periods by using triplicate groups of 110 rainbow trout with an average initial body weight of 3.0 g. Ergocalciferol (vitamin D2 or D2) and cholecalciferol (vitamin D3 or D3) were included to provide levels of 200, 400 and 800 iu/kg in a semipurified casein, gelatin diet. Further treatments with 0 vitamin D and 1600 iu/kg of D3 were also included. The resulting growth curves were significant for parallelism. Statistical analysis showed that D3 was 3.27 times as potent as D2 (limits 2.33 to 4.58). The dietary requirement for D3 was found to be in excess of 800 iu/kg of diet. Vitamin D-deficient fish showed no change in bone ash but exhibited clinical manifestations of tetany with no hypocalcemia. A complete absence of tetany was seen only in the groups fed 800 and 1600 iu of D3 per kilogram. None of the levels of D2 used were sufficient to completely alleviate symptoms of this disorder. These studies of rainbow trout provide evidence that vitamin D is required for the normal functioning of white muscle without altering the calcium content of the plasma or epaxial musculature.ergocalciferol cholecalciferol muscular development requirements trout

Alloferon improves the growth performance and developmental time of mealworms (Tenebrio molitor)

Mealworms (Tenebrio molitor) are important food sources for reptiles, birds, and other organisms, as well as for humans. Due to their outstanding nutritional value, mealworms are in high demand as an alternative food source and are the subject of widespread curiosity. However, the slow growth and low survival rate of mealworms cause problems for mass production. Since alloferon, a synthetic peptide, showed long-term immunological effects on mealworms, we hypothesized that alloferon would function as a growth promoter to maximize mealworm production. We discovered that the overall weight of the alloferon-containing gelatin diet group was 39.5-90% heavier, and the development time of the experimental group was shortened up to 20.6-39.6% than the control group. In addition, 300 nM alloferon significantly boosted cell proliferation of Sf9 cells (insect cells) only after six days of the treatment. Also, we noticed that two proteins were induced in alloferon fed mealworm body tissue and found that one of the proteins was phenoloxidase 1, which may be responsible for increasing growth rate by regulating the production of melanin pigments. Overall, these findings have potential implications in mealworm insect farming because alloferon may foster a sustainable food supply industry.

Pseudocapillaria tomentosa in laboratory zebrafish Danio rerio: patterns of infection and dose response.

Parasites in wild populations almost always exhibit aggregation (overdispersion), in which relatively few hosts are infected with high numbers of the parasites. This pattern of infection has also been observed in laboratory studies, where many of the sources of natural variation are removed. Pseudocapillaria tomentosa (Nematoda) is common in zebrafish (Danio rerio) facilities. We describe here patterns of infections in zebrafish experimentally infected with larvated P. tomentosa eggs in various trials with defined numbers of eggs. One trial with eggs delivered in a gelatin diet is also included. Fish were exposed at 25, 75, and 200 eggs fish-1, and the minimal infectious dose was estimated to be 1.5 eggs fish-1. The ID50 (50% infective dose) was calculated to be 17.5 eggs fish-1. We also included data from a trial and 2 previously published experiments with undefined doses in which zebrafish were exposed to infectious water and detritus from a tank that previously contained infected fish. All doses resulted in a high prevalence of infection (>70%), except at the 25 eggs fish-1 dose, where the prevalence was 43-46%. Mean abundance of worms corresponded to dose, from 0.57 worms fish-1 at 25 eggs fish-1 to 7 worms fish-1 at 200 eggs fish-1. Variance to mean ratios (V/M) and the k parameters showed aggregation across the 8 separate trials, including the gelatin diet. Aggregation increased with increased parasite abundance. Given the consistent observation of aggregation across our experiments, the zebrafish/P. tomentosa system provides a potentially robust, high-throughput model to investigate factors that influence differences in host susceptibility within defined populations.

Application of fish gelatin as diet binder in diets for the common carp Cyprinus carpio L. fingerlings

Fish gelatin applied as an animal source binder and stabilizer in diets for the common carp Cyprinus carpio L. fingerlings in comparison with binder void diet. Experimental diets prepared from standard raw materials adding laboratory made fish gelatin at 1% as binder. Three types of gelatin applied (extracted from tilapia Tilapia zilli skins, common carp Cyprinus carpio L. gas bladder and barred needlefish Ablennes hians heads). Three diets containing each type of extracted gelatin were prepared to compare with gelatin void diet. Fish initial average weight 5.56 gm were fed at 5% body weight daily. Chemical and physical analyses performed on pellets thrown into water to feed fish as affected by added gelatin. The influences of gelatin monitored on pellet density, floating period, sinking velocity, water absorption rate and disintegrating rate as indicators for pellet quality and resistance into water. Feed intake by fish during research period studied also. Results showed that bladder gelatin diet gave the highest weight increase in comparison with other diets which reached 15.6gm. Physical measurements demonstrated that the highest density recorded in bladder gelatin diet (1.4 gm/cm 3 ) followed by head and skin gelatin diets (1.3 gm/cm 3 ) while the lowest density recorded in gelatin void diet (1.1 gm/cm 3 ). Floating time of 8.55 sec. and sinking velocity of 1.06 sec./cm recorded for bladder gelatin diet in comparison with 7.53, 7.31 and 5.30 sec. for floating time and 1.37, 1.43 and 2.47 sec./cm for sinking velocity of diets containing head , skin gelatin and control, respectively. Various treatment indicated impacts on growth where weight increase rated 10.26-15.6 g, specific growth rate 1.10-1.61 and relative growth rate 39.46-62.40 %. Bladder gelatin diet surpassed others in weight increase, specific and relative growth rates. Feed conversion ratios reached 3.156, 2.862, 3.597 and 4.306 for skin, bladder, head gelatin and control diets, respectively. As for feed intake, bladder gelatin treatment gave the highest values. Chemical composition did not affected by using binders.

SUPPLEMENTARY FOOD IN THE DIET OF THE TERRESTRIAL ISOPOD PORCELLIO SCABER LATR. (ISOPODA: ONISCIDEA)

ABSTRACT In laboratory experiments with Porcellio scaber, the primary food (Norway maple litter) was supplemented with artificial (gelatin, bran) or natural (feces) food sources. Total food consumption was similar, whereas the proportion of different food sources in the isopods' diet, as well as assimilation efficiency, varied greatly. Isopods grew best when the supplementary food was bran and gelatin, and their survival rate was also high on the bran and gelatin diet. The chemical composition of the (secondary) feces produced during the experiments also differed significantly between treatments. Nitrogen content and carbon to nitrogen ratio in secondary feces were lowest in the gelatin-supplemented regime. In the present experiments, feces did not increase fitness correlates as much as the artificial supplementary food, which may be partly due to the use of freshly produced dried feces which had not undergone microbial action.

2073 DIETARY HYDROXYPROLINE INDUCES NEPHROLITHIASIS IN THE ADULT PORCINE MODEL

You have accessJournal of UrologyStone Disease: Basic Research I1 Apr 20122073 DIETARY HYDROXYPROLINE INDUCES NEPHROLITHIASIS IN THE ADULT PORCINE MODEL Sutchin R. Patel, Kristina L. Penniston, Thomas D. Crenshaw, and Stephen Y. Nakada Sutchin R. PatelSutchin R. Patel Lake Bluff, IL More articles by this author , Kristina L. PennistonKristina L. Penniston Madison, WI More articles by this author , Thomas D. CrenshawThomas D. Crenshaw Madison, WI More articles by this author , and Stephen Y. NakadaStephen Y. Nakada Madison, WI More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.2239AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Our previous studies have shown that a 10% hydroxyproline and gelatin diet can both lead to long-term hyperoxaluria in the adult porcine model. However, no studies have shown nephrolithiasis formation in the adult porcine model. The purpose of our study was to evaluate both diets in the sow model for histologic crystal deposition and gross formation of nephrolithiasis. METHODS Two sows were fed a control diet and six sows were fed a diet of either 10% hydroxyproline or gelatin for 7, 14 and 21 days. Catheters were placed in the sows for 24 hour urine collection prior to the sows being sacrificed at either the 7 day, 14 day or 21 day timepoint. Both kidneys were removed and evaluated for gross stone formation. Renal tissue was fixed in formalin, stained with H&E and von Kossa and evaluated under light microscopy for calcium crystal deposition. Urine was analyzed via ion chromatography for oxalate. RESULTS Mean urinary oxalate concentration for sows on the control diet was 74 mg/L. Urinary oxalate concentrations for the 10% HP diet were 147, 352 and 89 mg/L at 7, 14 and 21 days. Urinary oxalate concentrations for the gelatin diet were 46, 4 and 132 mg/L at 7, 14 and 21 days. Histology revealed calcium crystal formation in the distal collecting ducts and renal papillae in one kidney of the 21 day, 10% hydroxyproline diet sow. Gross pathology revealed 7 renal calculi and calcification at the papillary tips in the same kidney of the 21 day, 10% hydroxyproline diet sow. Chemical analysis of the calculi revealed a composition of 20% calcium oxalate monohydrate, 78% calcium oxalate dihydrate and 2% protein. CONCLUSIONS A long-term 10% hydroxyproline diet leads to calcium oxalate nephrolithiasis in the adult porcine model. This is the first reported case of calcium stone formation in the adult porcine model and has important implications in the development of a dietary porcine model for urolithiasis. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e836 Peer Review Report Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Sutchin R. Patel Lake Bluff, IL More articles by this author Kristina L. Penniston Madison, WI More articles by this author Thomas D. Crenshaw Madison, WI More articles by this author Stephen Y. Nakada Madison, WI More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Dietary Induction of Long-Term Hyperoxaluria in the Porcine Model

The purpose of our study was to determine if a hydroxyproline (HP) or gelatin diet could induce long-term hyperoxaluria in the porcine model. A total of 18 gravid crossbred sows (Large White × Landrace) were randomly allotted into three treatment groups: 5% HP, 10% HP, and gelatin diet. All sows were catheterized 1 day before starting treatment diet. Catheters were left in place for 5 days before being removed. Sows were recatheterized for urine collections on days 11 to 12 and days 21 to 22. Urine was collected for each entire 24-hour period, and urinary oxalate was determined by ion chromatography. Urinary oxalate concentrations for all three diets peaked within the first 5 days of the diet. The sows fed the 5% HP, 10% HP, and gelatin diets had an early peak in urinary oxalate concentration (mg/L) at day 2 (158% increase), day 5 (316% increase), and day 5 (830% increase), respectively. The day 21 to 22 time points in all three diets demonstrated markedly increased urinary oxalate concentrations in comparison with baseline, with some concentrations higher than the early time point peaks (day 22: 5% HP=1906% increase, P=0.12; 10% HP=640% increase, P=0.02; gelatin=501% increase, P=0.01). Although both the 10% HP and gelatin diets induce significant short- and long-term hyperoxaluria in the porcine model, the gelatin diet is more cost-effective. The ability to induce long-term hyperoxaluria has important implications in establishing a porcine model for oxalate urolithiasis.

2050 HYDROXYPROLINE AND GELATIN DIETS INDUCE LONG-TERM HYPEROXALURIA IN THE PORCINE MODEL

You have accessJournal of UrologyStone Disease: Basic Research1 Apr 20112050 HYDROXYPROLINE AND GELATIN DIETS INDUCE LONG-TERM HYPEROXALURIA IN THE PORCINE MODEL Sutchin R. Patel, Kristina L. Penniston, Lauren Iwicki, Ibrahim Saeed, Thomas D. Crenshaw, and Stephen Y. Nakada Sutchin R. PatelSutchin R. Patel Madison, WI More articles by this author , Kristina L. PennistonKristina L. Penniston Madison, WI More articles by this author , Lauren IwickiLauren Iwicki Madison, WI More articles by this author , Ibrahim SaeedIbrahim Saeed Madison, WI More articles by this author , Thomas D. CrenshawThomas D. Crenshaw Madison, WI More articles by this author , and Stephen Y. NakadaStephen Y. Nakada Madison, WI More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.2281AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Swine models have been useful in the study of many different disease processes, but the anatomic and physiologic renal similarities between sows and humans make them a promising model for the study of nephrolithiasis. Previous porcine research has shown that a 5% hydroxyproline diet can lead to short-term induction of hyperoxaluria with a decrease in urinary oxalate by day 5. A gelatin diet has been shown in humans to induce hyperoxaluria. The purpose of our study was to determine if a hydroxyproline or gelatin diet could induce long-term hyperoxaluria in the porcine model. METHODS A total of 9 gravid crossbred sows (Large White x Landrace) were randomly allotted into 3 treatment groups: 5% Hydroxyproline, 10% Hydroxyproline and Gelatin diet. All sows were catheterized one day prior to starting treatment diet. Catheters were left in place for 5 days prior to being removed. Sows were recatheterized for urine collection on day 21. Urine was collected for each entire 24 hour period in order to control for differences in the diurnal and postprandial variations in the renal handling of oxalate. Urinary oxalate was determined by ion chromatography. RESULTS In the 5% hydroxyproline diet, the percentage increase in urinary oxalate from baseline peaked to 133% on day 2 and was 288% on day 21. In the 10% hydroxyproline diet, the percentage increase in urinary oxalate from baseline peaked to 312% on day 3 and was 322% on day 21. In the gelatin diet, the percentage increase in urinary oxalate from baseline peaked to 331% on day 3 and was 317% on day 21. Paired Student's t-test confirmed that oxalate levels were significantly different from baseline in the 5% hydroxyproline diet on day 21 (p<0.001) and in the gelatin diet on days 3 and 21 (p=0.02 and p=0.03). To further confirm that the treatment diets had the expected impact on urinary oxalate, mass spectrometry was used to confirm increased urinary glycolate in a subset of the samples. CONCLUSIONS All three treatment diets lead to the induction of long-term hyperoxaluria in a porcine model. The gelatin diet induced statistically significant hyperoxaluria over the greatest number of time points among the three treatment groups. The ability to induce long-term hyperoxaluria has important implications in establishing a porcine model for calcium oxalate urolithiasis. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e820-e821 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Sutchin R. Patel Madison, WI More articles by this author Kristina L. Penniston Madison, WI More articles by this author Lauren Iwicki Madison, WI More articles by this author Ibrahim Saeed Madison, WI More articles by this author Thomas D. Crenshaw Madison, WI More articles by this author Stephen Y. Nakada Madison, WI More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Single-Protein Casein and Gelatin Diets Affect Energy Expenditure Similarly but Substrate Balance and Appetite Differently in Adults 1–3

Increasing the protein content of a diet results in increased satiety and energy expenditure (EE). It is not clear whether the magnitude of these effects differs between proteins differing in concentrations of indispensable amino acids (IAA). We hypothesized that a protein lacking IAA may stimulate appetite suppression and EE and may limit positive protein balance. Therefore, we compared appetite, EE, and substrate balances between gelatin (incomplete protein) and casein (complete protein) in single-protein diets with either 25 or 10% of energy (En%) from protein. During a 36-h stay in a respiration chamber, 23 healthy men (n = 11) and women (n = 12) (BMI, 22.2 ± 2.3 kg/m2; age, 25 ± 7 y) consumed 4 isoenergetic diets: 25 En% (25/20/55 En% protein/fat/carbohydrate) and 10 En% (10/35/55 En% protein/fat/carbohydrate) casein or gelatin diet in a randomized crossover design. For 3 d before the study, participants consumed a diet at home with similar macronutrient distribution as the diet they would receive during the subsequent stay in the chamber. Hunger was suppressed 44% more (P < 0.05) and protein balance was more negative when consuming the 10 En% gelatin diet (-0.17 ± 0.03 MJ/d) compared with the 10 En% casein diet (−0.07 ± 0.03 MJ/d; P < 0.05); carbohydrate and fat balances did not differ between the treatments. EE did not differ when participants consumed the 25 En% or 10 En% diets. Participants were in higher protein balance (0.56 ± 0.05 vs. 0.30 ± 0.04 MJ/d; P < 0.0001), lower carbohydrate balance (0.86 ± 0.14 vs. 1.37 ± 0.17 MJ/d; P < 0.01), and similar negative fat balance when they consumed the 25 En% casein compared with the 25 En% gelatin diet. In conclusion, when we compared the effects of an incomplete protein (gelatin) and a complete protein (casein) at 2 concentrations over 36 h, gelatin resulted in a greater appetite suppression; casein caused a greater positive (smaller negative) protein balance, and effects on EE did not differ. In terms of weight loss for people with obesity, the greater hunger-suppressing effect of gelatin may play a role in reducing energy intake if this effect is maintained when consuming a gelatin diet in the long term. In addition, long-term use of casein may contribute to preservation of fat-free mass.

Comparison of 2 diets with either 25 or 10 energy% gelatin on energy expenditure, substrate balances and appetite profile

Summary Background & aims Increasing the protein content of a diet results in increased satiety and energy expenditure. It is unknown to what extent gelatin has such effects. We compared satiety and energy expenditure in subjects on 2 single-protein diets with either 25% or 10% of energy (En%) from gelatin. Methods During 36 h in a respiration chamber, 24 healthy subjects (BMI 22.4 ± 2.4 kg/m2; age 25 ± 7 y) received subject specific isoenergetic diets: 25En% (25/20/55En%-protein/fat/carbohydrate) and 10En% gelatin diet (10/35/55En%-protein/fat/carbohydrate), in a randomised crossover design. Three days before, subjects consumed a diet with similar macronutrient composition at home. Results The 25En% compared with the 10En% gelatin diet resulted in a 2.1 ± 1.0% higher 24-h energy expenditure (9.20 ± 0.23 vs. 9.01 ± 0.23 MJ/d, P Conclusions In the short-term a 25En% compared with a 10En% gelatin diet boosts energy expenditure, promotes a positive protein and negative fat balance, and reduces hunger.

Single protein casein and gelatin diets induce similar effects on energy expenditure, but different effects on substrate balance and appetite

Single protein casein and gelatin diets induce similar effects on energy expenditure, but different effects on substrate balance and appetite

Lagomorph and rodent responses to two protein hydrolysates

Various species of rodents and lagomorphs were used in bioassays to determine the effectiveness of protein hydrolysates (specifically hydrolyzed casein and gelatin) as herbivore repellents. Mixed sex groups of captive rabbits, pocket gophers, voles, and mountain beavers were offered hydrolyzed casein or gelatin test diets in single-choice tests following a training period with a hydrolysate-free diet. The effectiveness of either hydrolyzed casein or gelatin was dependent on the species. Hydrolyzed casein was identified as an effective repellent for mountain beavers and pocket gophers as these species showed a strong avoidance of hydrolyzed casein diets. Rabbits demonstrated slightly higher avoidance of the gelatin diets versus hydrolyzed casein. However, hydrolyzed casein and gelatin displayed little potential as repellents for voles as both products were readily consumed. Rather than universal application for all pest herbivores, test diet preferences suggest that repellent application depends on the pest species.

Hydroxyproline ingestion and urinary oxalate and glycolate excretion

Endogenous synthesis of oxalate is an important contributor to calcium oxalate stone formation and renal impairment associated with primary hyperoxaluria. Although the principal precursor of oxalate is believed to be glyoxylate, pathways in humans resulting in glyoxylate synthesis are not well defined. Hydroxyproline, a component amino acid of collagen, is a potential glyoxylate precursor. We have investigated the contribution of dietary hydroxyproline derived from gelatin to urinary oxalate and glycolate excretion. Responses to the ingestion of 30 g of gelatin or whey protein were compared on controlled oxalate diets. The time course of metabolism of a 10 g gelatin load was determined as well as the response to varying gelatin loads. Urinary glycolate excretion was 5.3-fold higher on the gelatin diet compared to the whey diet and urinary oxalate excretion was 43% higher. Significant changes in plasma hydroxyproline and urinary oxalate and glycolate were observed with 5 and 10 g gelatin loads, but not 1 and 2 g loads. Extrapolation of these results to daily anticipated collagen turnover and hydroxyproline intake suggests that hydroxyproline metabolism contributes 20-50% of glycolate excreted in urine and 5-20% of urinary oxalate derived from endogenous synthesis. Our results also revealed that the kidney absorbs significant quantities of hydroxyproline and glycolate, and their metabolism to oxalate in this tissue warrants further consideration.

Effect of Diets Formulated with Native Peruvian Plants on Growth and Feeding Efficiency of Red Pacu (Piaractus brachypomus) Juveniles

Abstract We evaluated the effects of casein‐based semipurified diets, alone or supplemented with native Peruvian plants, on growth, feed efficiency, and histology of the digestive tract of red pacu, Piaractus brachypomus, juveniles over an 8‐wk feeding trial. Three tanks were randomly assigned to one of four casein–gelatin (40:8) diets containing a supplement of 15% wheat meal (control) or an identical level of substitution of three South American native plant as follows: camu‐camu fruit (Myrciaria dubia), aguaje fruit (Mauritia flexuosa), or maca tuber meal (Lepidium meyenii). The fish (initial weight, 2.04 ± 0.06 g) were fed experimental diets at decreasing feeding rates from 4 to 2.6% of body weight. After 8 weeks of feeding, fish fed a diet supplemented with maca meal showed significantly higher (P &lt; 0.05) weight gain, specific growth rate, protein efficiency ratio (PER), apparent net protein utilization (NPU), and instantaneous feed intake than fish fed other diets. Feed conversion ratio (FCR), PER, and NPU in fish fed the casein–gelatin diet supplemented with maca meal were among the best ever reported in the scientific literature, 0.64 ± 0.03, 3.13 ± 0.15 and 23.8 ± 2.0, respectively. The camu‐camu meal had a negative impact on diet palatability and utilization, which resulted in slower growth. The stomach, intestine, pancreas, and pyloric caeca at the start and end of the experiment showed normal differentiation and appearance of cells and tissues. The liver parenchyma showed lipid infiltration and pigment accumulation in all samples at the initiation of the experiment and may be attributed to the period of decreased feed intake prior to the study. At the end of the study, similar histopathologies were recorded in all samples from the control and camu‐camu groups. Normal liver histology (polyhedral hepatocytes with centrally located nuclei) was observed in two of three samples from the maca group and all the samples from the group that was fed the aguaje‐supplemented diet.

Individual food intake measurement of freshwater crayfish (Pacifastacus leniusculus Dana) juveniles

The inert marker method for individual food intake measurement of signal crayfish (Pacifastacus leniusculus Dana) juveniles (carapace length (CL) ranged from 16.5 to 25.6 mm and wet weight (WW) from 0.88 to 4.47 g) was evaluated in a series of experiments. The measurement technique was tested with two types of diet: a gelatin-based semi-moist diet and an agar-based dry diet. Diets were labelled with X-ray dense ballotini glass beads. After feeding, juveniles were X-rayed, and the amount of ingested glass beads in the digestive track was counted from the X-ray images. The method proved reliable only with the gelatin diet. In the ingested gelatin food, 92.80±8.55% of the glass beads originally in the food were found in comparison with 40.99±24.72% for the agar diet. Subsequently, the growth efficiency of the gelatin diet was compared with typically used raw fish diet (roach, Rutilus rutilus L.), and possible harmful effects of X-raying on the growth and survival of the juveniles were tested on 2-year-old crayfish (CL 22.90±1.66 mm and WW 3.15±0.71 g). Roach-fed juveniles grew significantly faster than the gelatin-fed counterparts. However, the growth performance and survival of the juveniles on gelatin diet was considered good enough to allow long-term growth experiments with individual feed intake monitoring, e.g. for studies on social behaviour of the crayfish. The results of this study confirmed that the X-radiography technique together with a semi-moist gelatin-based diet makes it possible to measure individual food consumption of freshwater crayfish juveniles reared communally.

Habitual tea consumption protects against the inhibitory effects of tea on iron absorption in rats

The hypothesis of this study was that tea inhibits iron absorption in animals unaccustomed to tea consumption but not in animals habituated to high intakes of tea. Three diets were prepared: 1) tannin-free diet; 2) 5% tea solids (tea) diet; and 3) 5% tea solids + 6% gelatin (T/G). Gelatin was chosen as a proxy for salivary proline–rich proteins (PRP). Five groups of rats were assigned to the following treatments: 1) control (tannin-free diet throughout), 2) short-term tea (tannin-free except tea diet on day 8, 3) long-term tea (tea diet throughout), 4) short-term T/G (tannin-free except tea with gelatin diet on day 8, and 5) long-term T/G (tea with gelatin diet throughout). After 10 days of dietary treatment, iron absorption, measured using 59Fe, was 41%, 7%, 25%, 7%, and 21% for treatments 1, 2, 3, 4, and 5, respectively. Rats in groups 3 and 5 showed higher PRP than control. We conclude that rats possess adaptive mechanisms for partially overcoming the inhibitory effects of tannins on iron absorption possibly by increasing secretion of PRP in saliva.

Effects of dietary protein and fat on cholesterol and fat metabolism in rats

The influence of two fat sources (soybean oil and a 4:1 mixture of coconut oil and soybean oil) fed at three different levels (5, 10 and 20% by weight) and two protein sources (casein and gelatin supplemented with limiting amino acids) on cholesterol and fat metabolism in rats was determined. Fat or protein type had a significant ( P < 0.05) influence on serum triacylglycerols; protein type had a significant effect on serum total cholesterol; while fat level had no effect on these parameters. In general, the concentrations of serum triacylglycerols and total cholesterol were higher ( P < 0.05) in rats fed casein diets compared to those fed gelatin diets. A pronounced effect of source of protein and fat was also observed on de novo fat synthesis and cholesterol kinetics. De novo fat synthesis was highest in animals fed gelatin-soybean oil diets. De novo cholesterol synthesis followed the same patterns observed for fat synthesis. Since overall serum cholesterol levels were lower in rats fed gelatin-soybean oil diets, cholesterol clearance rates must have been higher to compensate for the increased synthesis observed in rats fed these diets.

Dietary induction of angiotensin-converting enzyme in proximal and distal rat small intestine.

Induction of angiotensin-converting enzyme was examined in proximal and distal intestinal segments of rats fed a low-protein (4%) diet and then switched to a high-protein (gelatin) diet. Animals were killed at varying time points, and brush-border membranes and total RNA were prepared from the segments. In the proximal intestine, there was a fivefold increase in angiotensin-converting enzyme levels after 14 days but only a twofold change in mRNA. In the distal intestine, there was no increase in enzyme activity but mRNA increased 2.4-fold. Organ culture was used to measure changes in enzyme biosynthesis. There was a 5- to 6-fold increase in the biosynthesis of angiotensin-converting enzyme in the proximal intestine 24 h after the switch to the gelatin diet and a 1.6-fold increase in mRNA levels. No change in biosynthesis was observed in the distal small intestine despite an increase in mRNA. These results support the conclusion that rapid dietary induction of intestinal angiotensin-converting enzyme is differentially regulated in proximal and distal segments of the small intestine.