The impact of moving from conventional to precision feeding systems in growing-finishing pig operations on animal performance, nutrient utilization, and body and carcass composition was studied. Fifteen animals per treatment for a total of 60 pigs of 41.2 (SE = 0.5) kg of BW were used in a performance trial (84 d) with 4 treatments: a 3-phase (3P) feeding program obtained by blending fixed proportions of feeds A (high nutrient density) and B (low nutrient density); a 3-phase commercial (COM) feeding program; and 2 daily-phase feeding programs in which the blended proportions of feeds A and B were adjusted daily to meet the estimated nutritional requirements of the group (multiphase-group feeding, MPG) or of each pig individually (multiphase-individual feeding, MPI). Daily feed intake was recorded each day and pigs were weighed weekly during the trial. Body composition was assessed at the beginning of the trial and every 28 d by dual-energy X-ray densitometry. Nitrogen and phosphorus excretion was estimated as the difference between retention and intake. Organ, carcass, and primal cut measurements were taken after slaughter. The COM feeding program reduced (P < 0.05) ADFI and improved G:F rate in relation to other treatments. The MPG and MPI programs showed values for ADFI, ADG, G:F, final BW, and nitrogen and phosphorus retention that were similar to those obtained for the 3P feeding program. However, compared with the 3P treatment, the MPI feeding program reduced the standardized ileal digestible lysine intake by 27%, the estimated nitrogen excretion by 22%, and the estimated phosphorus excretion by 27% (P < 0.05). Organs, carcass, and primal cut weights did not differ among treatments. Feeding growing-finishing pigs with daily tailored diets using precision feeding techniques is an effective approach to reduce nutrient excretion without compromising pig performance or carcass composition.

The teleost fish Leporinus obtusidens (piava) was exposed to different concentrations of Roundup, a commercial herbicide formulation containing glyphosate (0, 1, or 5 mg L(-1)), for 90 days. Acetylcholinesterase (AChE) activity was verified in brain and muscle. Hepatic and muscular metabolic parameters as well as some hematological parameters were determined. The results showed that brain AChE activity was significantly decreased in fish exposed to 5 mg L(-1) Roundup, whereas muscular AChE activity was not altered. Both Roundup concentrations significantly decreased liver glycogen without altering the muscle glycogen content. Hepatic glucose levels were reduced only in fish exposed to 5 mg L(-1) Roundup. Lactate levels in the liver and muscle significantly increased in fish exposed to both Roundup concentrations. Hepatic protein content remained constant at 1 mg L(-1) but increased at 5 mg L(-1) Roundup. In the muscle however, protein content decreased with increasing exposure concentration. The herbicide exposure produced a decrease in hematological parameters at both concentrations tested. The majority of observed effects occur at environmental relevant concentrations, and in summary, the results show that Roundup affects brain AChE activity as well as metabolic and hematologic parameters of piavas. Thus, we can suggest that long-term exposure to Roundup causes metabolic disruption in Leporinus obtusidens.

RESUMO Foram testadas três fontes de lipídios em rações experimentais para juvenis de jundiá

No abstract

RESUMO O objetivo deste trabalho foi verificar o crescimento e a composição de filés de juvenis de jundiá (Rhamdia quelen) alimentados com diferentes fontes protéicas, durante 60 dias.Utilizaram-se 540 peixes (peso médio inicial=15,00±0,62g, comprimento total inicial=11,98±0,35cm)

The purpose of this study was to verify the effect of dietary Ca 2+ on the growth and survival of silver catfish fingerlings (Rhamdia quelen) exposed to different water pH (5.5, 7.5 and 9.0). Silver catfish fingerlings were randomly placed in a thermoregulated water re-use system with twelve 250 L-tanks, two 1000 L-biofilters and a 2000 L-reservoir with a medium flow of 3.84 L min )1 tank. Stocking density was 0.16 fingerlings L )1 . To prepare the treatment diets, the control diet (0.8 g kg )1 Ca 2+ ) was supplemented with CaCO 3 to yield experimental diets with 6.4, 9.5 and 23.9 g kg )1 Ca 2+ . There were three replicates/treatments. Survival was more than 93.9% in all treatments. Exposure of silver catfish fingerlings to alkaline or acid water reduced growth, and this effect was not ameliorated by dietary Ca 2+ supplementation. Moreover, when fingerlings were maintained in water with pH 7.5, the best dietary Ca 2+ range for silver catfish fingerling growth was 0.8-6.4 g kg )1 . KEY WORDS

This study verified the efficacy of common salt (NaCl) in the food and water as a supportive therapy for Ichthyophthirius multifiliis and growth of silver catfish, Rhamdia quelen, fingerlings. After appearance of the first white spots following experimental exposure, indicating infestation by this parasite, fish were transferred to eighteen 40‐L polypropylene tanks and kept for 30 d. Experimental diets were prepared with five different levels of salt supplementation: 0.0, 1.2, 2.5, 5.0, and 6.0% for 30 d. In addition, another group of fish were fed a diet without salt supplementation but exposed to 4 g of salt/L of water. Fingerlings were collected at different times for analyses of whole‐body Na+, K+, and Cl−. Dietary salt supplementation provoked a transitory increase in whole‐body Na+, K+, and Cl− in infested catfish fingerlings, but the best stabilization of these ion levels was observed in specimens exposed to salt in the water. Silver catfish fed a diet containing 1.2% salt showed higher weight and biomass after 30 d compared to those fed with 6% salt. The use of 4 g of salt/L of water improved survival of infested silver catfish, but dietary salt supplementation was ineffective as a therapy for ichthyophthiriasis.

Digestive enzymes activity influence feed utilization by fish, and its understanding is important to optimize diet formulation. This study reports the digestive enzyme activities of jundiá juveniles fed diets with protein sources. Fish were fed six experimental diets for 90 days: MBY (meat and bone meal + sugar cane yeast), SY (soybean meal + sugar cane yeast), S (soybean meal), MBS (meat and bone meal + soybean meal), FY (fish meal + sugar cane yeast) and FS (fish meal + soybean meal), and then sampled every 30 days and assayed in two intestine sections for digestive enzymes -trypsin, chymotrypsin and amylase -activities; gastric protease was assayed in the stomach. Digestive and hepatosomatic index, intestinal quotient, digestive tract length and weight gain were also measured. Trypsin and chymotrypsin activities were higher (p < 0.0001) in fish fed diets containing animal protein sources (MBY, MBS, FY and FS diets). Alkaline proteases were negatively affected by dietary soybean meal in the SY and S diets. Amylase activity had greater variation between diets and intestine sections. Fish fed MBY and MBS diets showed higher gastric protease activity (p < 0.0001). Weight gains were higher in fish fed the MBS and FS diets (p < 0.05). Highest values (p < 0.05) of digestive tract length were observed in fish fed MBS and FY diets, but no correlation with enzymes activities was found. Hepatosomatic index (HSI) was affected by diet composition. Dietary composition influenced digestive enzymes activities of jundiá. Key words: digestion, nutrition, soybean meal, meat and bone meal, fish mealFontes protéicas e atividade de enzimas digestivas em jundiás (Rhamdia quelen) RESUMO: As enzimas digestivas influenciam a utilização dos alimentos em peixes, e seu conhecimento é importante para otimizar a formulação de dietas. Este trabalho descreve a atividade de enzimas digestivas em juvenis de jundiá alimentados com fontes protéicas. Os peixes foram alimentados com seis dietas (90 dias): MBY (farinha de carne e ossos + levedura de cana), SY (farelo de soja + levedura de cana), S (farelo de soja), MBS (farinha de carne e ossos + farelo de soja), FY (farinha de peixe + levedura de cana) e FS (farinha de peixe + farelo de soja). A cada 30 dias, foram analisadas as enzimas digestivas (tripsina, quimiotripsina e amilase) no intestino. No estômago, foi mensurada a protease ácida. Foram estimados os índices digestivo e hepato-somático, quociente intestinal, comprimento do trato digestório e ganho em peso.