Postprandial Nitrogen Excretion Research Articles

Candidate raw materials for a sustainable feeding of greater amberjack (Seriola dumerili) reared in recirculating aquaculture systems: Apparent digestibility, physical properties of diets and faeces, and postprandial nitrogen excretion

To evaluate the raw material digestibility, the physical characteristics of diet pellets and faeces, and the postprandial nitrogen excretion in greater amberjack (Seriola dumerili) reared in recirculating aquaculture systems (RAS), 10 diets were obtained by mixing a reference diet (CP: 51.8% DM; EE: 13.6% DM) with one of ten raw materials (7:3 ratio), i.e. fishmeal (FM), porcine haemoglobin (PH), fermented soybean (FS), soybean protein concentrate (SPC), hydrolysed wheat protein (HWP), potato protein (PP), beet pulp (BP), beer yeast without fat (BY), beer yeast with fat (BYF), and Lithothamnium seaweed (LS). Twenty fish (268.9 ± 94.3 g) were randomly distributed into 5 RAS tanks (4 fish per tank) and fed for 140 days the experimental diets. A Latin square experimental design was used based on 5 diets × 5 tanks for two rounds (10 ingredients, 2 weeks per diet per tank). The highest ADCs of dry matter and protein were recorded for PH (83.0% and 88.4%, respectively), FM (81.8% and 84.3%), SPC (77.4% and 82.5%), and BYF (73.0% and 80.9%) while the lowest ones for BY (64.4% and 70.8%), HWP (59.8% and 69.9%), PP (48.3% and 69.8%), and BP (53.7% and 55.8%) (p < 0.05). The ADCs of EAA were the highest for PH, FM and SPC compared to the other raw materials; ADCs of lipids was above 90% for all raw materials (p > 0.05). Regarding pellets properties, FM was associated with the highest value for oil leakage whereas BP to the lowest (0.18% vs. 0.11%; p < 0.05); FS, HWP, BYF, and PH produced less turbidity in water after 15 min than BY (3.68 mg L−1 on average vs. 6.01 mg L−1; p < 0.05). Regarding faeces size, fish fed FS, BYF, and FM produced the lowest volume of fresh faeces of fine-size class than those fed the other raw materials (62.1% vs. 69.2% on average; p < 0.05); the highest rate of dry faeces retained at a sieve mesh interval of 1.0 < mm < 1.2, was produced by fish fed BYF and the lowest rate by those fed BY (1.16% vs. 0.34%; p < 0.05). A maximum of postprandial nitrogen excretion (mg N-NH4+ × kgfish−1 × h) was reached between 2 and 4 h after feed ingestion without differences among diets (p > 0.05). Overall, the findings of this investigation will contribute to the sustainable formulation of RAS aquafeed optimized and tailored for this promising Mediterranean aquaculture species.

The effect of protein and lipid level on the specific dynamic action and post-prandial nitrogen excretion in subadult of white shrimp Litopenaeus vannamei

The study aimed to evaluate the effect of 4 levels of dietary protein (20, 30, 40 and 50%) and lipids (2, 4, 8 and 16%) on the magnitude and duration of specific dynamic action (SDA) and postprandial nitrogen excretion in the subadult white shrimp Litopenaeus vannamei using computer-controlled metabolic chambers (continuous-flow respirometer). We determined the oxygen consumption rate at 1 h intervals until the postprandial oxygen consumption rate returned to the pre-feeding level. Shrimp fed all the diets had significantly higher respiration rates after feeding due to the SDA. Oxygen consumption, the SDA coefficient and the SDA magnitude increased notably with increasing dietary protein content. Shrimp fed the 20% protein diet had the lowest levels of pre- and post-feeding respiration and the smallest SDA. A significant change in the SDA coefficient relative to each lipid level was not demonstrable. Additionally, nitrogenous excretion increased with an increase of dietary protein but not with an increase of lipid level. By estimating the SDA of subadults, the response to standard metabolic rate (SMR) was lower than that reported for juveniles and postlarva white shrimp

Effects of salinity on physiological conditions in juvenile common snook Centropomus undecimalis

This study describes the effects of different salinities on oxygen consumption, ammonia excretion, osmotic pressure, apparent heat increment, postprandial nitrogen excretion, and oxygen:nitrogen ratio in juvenile common snook Centropomus undecimalis. Oxygen consumption of fish fasting and fish feeding was statistically different in relation with salinity. Fish maintained at 0, 25, and 35 ppt invested more energy processing feed than fish maintained at 12 ppt. Fasting fish had lower ammonia excretion than feeding fish and excretion was reduced at high salinities. Snook can change the energetic substrate in function with salinity, from a mixture of protein and lipids and carbohydrates at 35 ppt to a more acute preference for proteins at lower salinities. This species changes osmotic plasma concentrations at extreme experimental salinities. The different salinities were the snook inhabits (0-36 ppt), have a direct effect on the physiology, inducing changes on the oxygen consumption, nitrogen excretion, changes on the energetic substrate and plasma osmotic pressure.

Metabolism and growth of juveniles of Litopenaeus vannamei: effect of salinity and dietary carbohydrate levels.

The present study was designed to understand how carbohydrate (CBH) and protein metabolism are related in the penaeid shrimp Litopenaeus vannamei. With this information, we obtained a comprehensive schedule of the protein-carbohydrate metabolism including enzymatic, energetic, and functional aspects. We used salinity to determine its role as a modulator of the protein-carbohydrate metabolism in shrimp. Two experiments were designed. The first experiment evaluated the effect of CBH-salinity combinations in growth and survival, and hemolymph glucose, protein, and ammonia levels, digestive gland glycogen, osmotic pressure, and glutamate dehydrogenase (GDH) of L. vannamei juveniles acclimated during 18 days at a salinity of 15 per thousand and 40 per thousand. The second experiment was done to evaluate the effect of dietary CBH level on pre- and postprandial oxygen consumption, ammonia excretion, and the oxygen-nitrogen ratio (O/N) of juvenile L. vannamei in shrimps acclimated at 40 per thousand salinity. We also evaluated the ability of shrimp to carbohydrate adaptation. We made phosphoenolpyruvate carboxykinase (PECPK) and hexokinase activity measurements after a change in dietary carbohydrate levels at different times during 10 days. The growth rate depended on the combination salinity-dietary CBH-protein level. The maximum growth rate was obtained in shrimps maintained at 15 per thousand salinity and with a diet containing low CBH and high protein. The protein in hemolymph is related to the dietary protein levels; high dietary protein levels produced a high protein concentration in hemolymph. This suggests hemolymph is able to store proteins after a salinity acclimation. Depending on the salinity, the hemolymph proteins could be used as a source of osmotic effectors or as metabolic energy. The O/N values obtained show that shrimp used proteins as a source of energy, mainly when shrimps were fed with low CBH. The role played by postprandial nitrogen excretion (PPNE) in apparent heat increase (AHI) (PPNE/AHI ratio) is lower in shrimps fed diets containing high CBH in comparison with shrimps fed diets containing low CBH levels. These results confirm that the metabolism of L. vannamei juveniles is controlled by dietary protein levels, affecting the processes involved in the mechanical and biochemical transformations of ingested food. A growth depression effect was observed in shrimps fed with low-CBH protein diets and maintained in 40 per thousand salinity. In these shrimps, the hemolymph ammonia concentration (HAC) was significantly higher than that observed in shrimps fed with low CBH and maintained in 15 per thousand salinity. That high HAC level coincided with lower growth rate, which suggests that this level might be toxic for juveniles of L. vannamei. Results obtained for GDH activity showed this enzyme regulated both HAC and hemolymph protein levels, with high values in shrimps fed with low CBH levels and maintained in 40 per thousand salinity, and lower in shrimps fed with high CBH and maintained in 15 per thousand salinity. These differences mean that shrimp with a high-gill GDH activity might waste more energy in oxidation of the excess proteins and amino acids, reducing the energy for growth. It was evident that L. vannamei can convert protein to glycogen by a gluconeogenic pathway, which permitted shrimp to maintain a minimum circulating glucose of 0.34 mg/ml in hemolymph. A high PECPK activity was observed in shrimps fed a diet containing low CBH level indicating that the gluconeogenic pathway is activated, as in vertebrates by low dietary CBH levels. After a change in diet, we observed a change in PEPCK; however, it was lower and seems to depend on the way of adaptation, because it occurred after 6 days when adapting to a high-CBH diet and with little change for the low-CBH diet.

Influence of dietary carbohydrate on the metabolism of juvenile Litopenaeus stylirostris.

The effect of dietary carbohydrates (CBH) on glucose and glycogen, digestive enzymes, ammonia excretion and osmotic pressure and osmotic capacity of Litopenaeus stylirostris juveniles was studied. The increase of CBH, ranging between 1 and 33%, stimulates activities of alpha-amylase and alpha-glucosidase in the hepatopancreas. High levels of glucose in hemolymph and of glycogen in the hepatopancreas were reached at the highest level of dietary CBH; however, the kinetics of accumulation is different. Shrimps fed with low level of CBH needed 3 h to reached glucose peak, whereas only 1 h is necessary for high CBH levels. A saturation curve was observed in glycogen level and alpha-amylase activity with maximum values in shrimp-fed diets containing 21% CBH. This level could be used to be included as a maximum shrimp dietary CBH level. Pre-prandial glycogen levels were observed in shrimp fed a diet containing 1% CBH, indicating an important gluconeogenesis, which affected the protein metabolism. The present results show that a diet containing 10% CBH may not be enough to cover the CBH requirement, which could be satisfied by dietary protein content. The low osmotic capacity observed in shrimp fed on a diet containing 10% CBH coincided with a relatively low post-prandial nitrogen excretion which reflects a low concentration of amino acids circulating in hemolymph, which affected the osmotic pressure and the osmotic capacity. These results reflect the high plasticity of shrimp species to use protein to obtain metabolic energy from food and its limited capacity for processing dietary CBH.

Oxygen consumption and ammonia-N excretion related to protein requirements for growth of white shrimp, Penaeus setiferus (L.), juveniles

An experiment was conducted to study the effect of protein level on the growth rate, survival, pre- and postprandial oxygen consumption, and ammonia (N-NH3) excretion in white shrimp. Penaeus setiferus (L.), juveniles. Diets containing 10%, 20%, 30%, 40% and 50% protein were provided at a proportion of 15% of the dry weight of shrimp weighing 0.19 ± 0.01g. The instantaneous growth rate was recorded for 45 days. The optimum protein level, in terms of the best growth rate, was that of the 30% protein diet (1.1 5g45days−1). All shrimp fed with the diets had significantly higher respiration rates after feeding because of the apparent heat increment (AHI). A greater postprandial nitrogen excretion (PPNE) excretion was also observed after feeding. Shrimp maintained on the 30% protein diet had the lowest AHI and PPNE coefficients (percentage of ingested energyl. and took the least time to reach the oxygen consumption and nitrogen excretion peak. The 0:N ratios varied according to protein level, with higher values (32 and 44, fasting and Feeding, respectively) with a 30% protein diet, and lower values (10 and 13. fasting and feeding, respectively) with 10% and 50% protein diets. These results indicate that P. setiferus juveniles use protein when fed with high (50%) and low (10%) protein diets, and lipid-protein substrates with a 30% protein diet. Under these conditions, P. setiferus grow better with a 30% protein diet where shrimp use food more efficiently.

Effect of feeding time on postprandial nitrogen excretion and energy expenditure in rainbow trout*1

Effect of feeding time on postprandial nitrogen excretion and energy expenditure in rainbow trout*1

Effect of feeding time on postprandial nitrogen excretion and energy expenditure in rainbow trout

The effect of feeding time (dawn or midnight) on nitrogen excretion and energy expenditure was studied in immature rainbow trout using measurements of respiratory gas exchange. Fish (mean individual weight 70 g) were maintained indoors under natural photoperiod and fed by hand (commercial food pellets) at a rate of 1% weight/day−1. Rates of ammonia and CO2 excretion and O2 uptake were measured every hour. Ammonia excretion increased immediately after feeding in fish fed at midnight, and 2h after feeding in fish fed at dawn. Ammonia excretion and energy supply from protein catabolism, were higher in trout fed at midnight than in those fed at dawn, while total energy expenditure was the same in both groups. The results suggested that trout fed in phase with their natural feeding rhythm use dietary protein more efficiently for growth than do trout fed out of phase with the natural rhythm.

Effect of Dietary Protein Level on Apparent Heat Increment and Post‐Prandial Nitrogen Excretion of Penaeus setiferus, P. schmitti, P. duorarum, and P. notialis Postlarvae

AbstractThe calorigenic effect of feeding (apparent heat increment, AHI) and post‐prandial nitrogen excretion (PPNE) were measured in postlarval (PL 25–30) Penaeus setiferus, P. schmitti, P. duorarum and P. notialis fed a fixed ration of 3 mg/animal using purified diets with 40, 50, 60, or 65% protein. Both AHI and PPNE increased with increasing dietary protein. The contribution of PPNE to AHI varied from 6.1 to 94%, with lesser values for P. setiferus and greater ones for P. duorarum. Also, the AHI coefficient (percentage of ingested energy) increased with increasing dietary protein. The AHI and PPNE coefficients for the four shrimp species ranged from 0.3 to 6.5% and 0.02 to 5.04% of ingested energy, respectively. These results suggest close relationships among protein requirements, the capacity to use dietary proteins as a source of energy, and adaptation by different species to different types of food. The amount of energy used for production of ammonia is proposed as an adequate measure of the part played by dietary proteins in food cost.

Effects of dietary protein/energy ratio, ration size, dietary energy source and water temperature on nitrogen excretion in rainbow trout

Postprandial nitrogen excretion was measured on groups of rainbow trout of mean body weight (MBW) 35g, fed, from maintenance to near satiation, diets containing graded levels of digestible energy (14 to 20 kJ/g dry matter) with digestible protein (DP)/digestible energy (DE) ratios of 18 and 23 mg/kJ at each protein level (DP: 32.5 or 37% dry matter). Irrespective of the diet and the ration size, urea-N excretion amounted to 15-16% of ammonia-N excretion. The higher the dietary DP/DE ratio, the greater was the amount of ammonia excreted. At high ration levels (1.5% and 2% of MBW/d), N excretion was 39-40% of digestible N intake for diets with a DP/DE ratio of 18 mg/kJ and 44% of digestible N intake for diets with a DP/DE ratio of 23 mg/kJ irrespective of the dietary protein level. At lower ration levels, N excretion as percent of N intake was higher than at higher feeding levels. Another experiment was performed to compare the effect of dietary lipid and digestible carbohydrate on ammonia excretion in rainbow trout reared at two water temperatures (8°C and 18°C). Neither water temperature nor dietary sources of non-protein energy had any significant effect on N excretion expressed as proportion of digestible N intake.

Effects of dietary protein/energy ratio, ration size, dietary energy source and water temperature on nitrogen excretion in rainbow trout

Postprandial nitrogen excretion was measured on groups of rainbow trout of mean body weight (MBW) 35g, fed, from maintenance to near satiation, diets containing graded levels of digestible energy (14 to 20 kJ/g dry matter) with digestible protein (DP)/digestible energy (DE) ratios of 18 and 23 mg/kJ at each protein level (DP: 32.5 or 37% dry matter). Irrespective of the diet and the ration size, urea-N excretion amounted to 15-16% of ammonia-N excretion. The higher the dietary DP/DE ratio, the greater was the amount of ammonia excreted. At high ration levels (1.5% and 2% of MBW/d), N excretion was 39–40% of digestible N intake for diets with a DP/DE ratio of 18 mg/kJ and 44% of digestible N intake for diets with a DP/DE ratio of 23 mg/kJ irrespective of the dietary protein level. At lower ration levels, N excretion as percent of N intake was higher than at higher feeding levels.Another experiment was performed to compare the effect of dietary lipid and digestible carbohydrate on ammonia excretion in rainbow trout reared at two water temperatures (8°C and 18°C). Neither water temperature nor dietary sources of non-protein energy had any significant effect on N excretion expressed as proportion of digestible N intake.

Postprandial metabolic changes in larval and juvenile carp (Cyprinus carpio).

Ammonia-nitrogen excretion and oxygen consumption rates after a meal were followed in carp larvae and juveniles of different sizes, starting from early exogenous feeding and until they had reached about 1 g of body weight. There was an immediate rise in the nitrogen excretion rate after feeding; the amplitude and duration of this increase were affected by body weight (BW) and the amount of nitrogen consumed (NI) and could be described by the equation: 37.61 BW-0.311 NI0.802. Endogenous nitrogen excretion rate and basal metabolic rate were affected by both nutritional status and previous nutritional history. A model used to describe the postprandial nitrogen excretion pattern in young carp fitted well with the experimental data. The different coefficients of the model were affected by body weight.