Dwight J Shawk, Mike D Tokach, Robert D Goodband, Steve S Dritz, Jason C Woodworth, Joel M DeRouchey, Annie B Lerner, Fangzhou Wu, Carine M Vier, Madison M Moniz, Kayla N Nemechek

本研究开展3个试验研究7-12kg猪日粮中钠、氯的来源与水平对生长性能的影响。 在所有试验中，仔猪断奶后7-8d饲喂同样的基础日粮(0.33%钠，0.77%氯)，然后随机分至各处理组。

试验一，360头不同性别的仔猪进行14天的试验，每个处理15个重复，每个圈6头猪。试验处理包括：10%乳清粉+盐的一个日粮(0.37%钠，0.75%氯);7.2%乳糖的三个日粮，分别添加0.35%盐(0.18%钠和0.47%氯)、0.78%盐(0.35%钠和0.72%氯)，或者添加1.15%小苏打和0.4%氯化钾(0.35%钠和0.45%氯)。0.78%盐+乳糖组猪只日增重显著高于0.35%盐+乳糖组，其它处理日增重在这两组之间。

试验二，使用360头去势公猪，试验期14天，每个处理12个重复，每圈5头猪。试验处理包括两个添加盐的处理(分别提供0.13%钠、0.35%氯或0.57%钠和0.68%氯)，另外两个日粮钠和氯由氯化钾和小苏打提供，分别为0.13%钠和0.35%氯、0.57%钠和0.5%氯，还有一个日粮添加小苏打和氯化钙(0.35%钠和0.5%氯)。无论钠的来源是哪个，猪日增重和采食量随着钠水平从0.13%到0.35%而增加(二次线性，P<0.05)，未观察到其它作用效果。氯化钠和小苏打处理之间没有显著性，相同钠和氯浓度但是不同来源之间也没有显著性差异。

试验三，使用3300头仔猪进行21天试验，每个处理10个重复，每个重复5头猪。对照组日粮中添加有盐，提供0.33%钠和0.55%氯，其它五个处理中钠含量为0.33%，通过添加氯化钾提供0.09%、0.21、0.32、0.45、0.55%氯。随着氯含量从0.09%提高至0.32%，猪的日增重和肉料比显著提高(二次线性，P<0.035)。对照组和0.55%氯组日增重相似。对于日增重和采食量来说，折线模型的结果发现最适氯水平为0.23%。对于肉料比来说，二次多项式模型发现氯的最适添加量为0.38%。

总之，7-12kg猪日粮中添加最少0.35%钠和0.38%氯可以获得更好的日增重和肉料比，并且本试验中使用的不同来源钠和氯之间没有差异。

Effects of sodium and chloride source and concentration on nursery pig growth performance

Dwight J Shawk, Mike D Tokach, Robert D Goodband, Steve S Dritz, Jason C Woodworth, Joel M DeRouchey, Annie B Lerner, Fangzhou Wu, Carine M Vier, Madison M Moniz, Kayla N Nemechek

Three studies were conducted to determine the effects of source and concentration of Na and Cl on pig growth performance from 7 to 12 kg. In all three experiments, pigs were fed a common diet (0.33% Na and 0.77% Cl) for 7 or 8 d after weaning then randomly assigned to dietary treatments. In Exp. 1, 360 mixed-sex pigs were used in a 14-d study with 15 replications per treatment and six pigs per pen. Treatments included a 10% dried whey diet with 0.60% added salt (0.37% Na and 0.75% Cl); or three diets with 7.2% crystalline lactose with either: 0.35% added salt (0.18% Na and 0.47% Cl); 0.78% added salt (0.35% Na and 0.72% Cl); or 1.15% NaHCO3 and 0.40% KCl (0.35% Na and 0.45% Cl). Pigs fed the 0.78% added salt-lactose diet had greater (P < 0.05) ADG than pigs fed the 0.35% added salt-lactose diet, with others intermediate. In Exp. 2, 360 barrows were used in a 14-d study with 12 replications per treatment and five pigs per pen. Treatments included two added salt diets (providing 0.13% Na and 0.35% Cl or 0.35% Na and 0.68% Cl), three diets with Na and Cl provided by KCl and NaHCO3 (0.13%, 0.35%, or 0.57% Na and 0.50% Cl), or a diet with NaHCO3 and CaCl2 (0.35% Na and 0.50% Cl). Regardless of Na source, ADG and ADFI increased (quadratic, P < 0.05) as dietary Na increased from 0.13% to 0.35%, with no further benefits observed thereafter. There was no evidence for differences among pigs fed NaCl or NaHCO3 nor evidence for differences among pigs fed the different Na and Cl sources at similar concentrations. In Exp. 3, 300 pigs were used in a 21-d trial with 10 replications per treatment and five pigs per pen. Treatments included a control diet with added salt to provide 0.33% Na and 0.55% Cl or five diets with 0.33 % Na and added KCl to provide 0.09, 0.21, 0.32, 0.45, or 0.55% Cl. ADG and G:F increased (quadratic, P < 0.035) as Cl increased from 0.09% to 0.32%. Pigs fed the control diet (added salt) and the 0.55% Cl diet had similar ADG. For ADG and ADFI, the broken line linear model indicated a breakpoint of 0.23% Cl. For G:F, the quadratic polynomial model suggested the maximum at 0.38% Cl. In conclusion, 7 to 12 kg pigs fed diets that contained at least 0.35% Na and 0.38% Cl had greater ADG and G:F compared to pigs fed diets with lower concentrations and minimal effects were observed among the sources of Na or Cl used in these studies.